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Learn Physics through songs – Gravity Song

Courtesy: http://www.songsforteaching.com/

Gravity is a pulling force
Take a big jump and see
You’ll always come down back onto Earth
Because the force of gravity

Objects in the universe
Are pulled towards each other
By a force called gravity

The bigger the object
The stronger the pull
A dog is more massive
Than an ant or a fly
But not as massive as a bull
Cats, bats, rats, hats,
Gnats, floor mats:
Which is heaviest or has the most mass?
CATS!

Objects in the universe
Are pulled towards each other
By a force called gravity

Objects in the universe
Are pulled towards each other
By a force called gravity

Gravity is a pulling force
Take a big jump and see
You’ll always come down
Back onto Earth
Because the force of gravity

Objects in the universe
Are pulled towards each other
By a force called gravity

Objects in the universe
Are pulled towards each other
By a force called gravity

A question from kinematics - motion in one dimension

Natasha Sehgal Asked:

"A stone is thrown in a vertically upward direction with a velocity of 5m/s. If the acceleration of the stone during its motion is 10m/s^2 in the downward direction , what will be the height attained by the stone and how much time will it take to reach there?"

Answer:

Take,

u=5m/s

a= -10 m/s²

v=0 at the topmost position

S= H_max = ?

The eqn of motion to use
v² - u² = 2aS
Which gives H = 1.25 m
From the eqn
v=u + at
t= 0.5 s

Now Plustwophysics is available on mobile too

Yes ! Now you can access plustwo physics while on the go! Just visit www.plustwophysics.com from your mobile and you will be automatically redirected to the mobile version
Now Enjoy learning physics from anywhere.

Find time of death of patient with differential equations

Mr. N.P. Sahani asked:

"The differential equation and solution for finding the time of death of a patient"

Answer:

See that the question is to find the time of death (Not predicting the time of death. I thought that when I read it first.)

I can give some links which will be helpful in this connection

1. http://www.exploreforensics.co.uk/estimating-the-time-of-death.html


2. http://en.wikipedia.org/wiki/Thermal_death_time


3. http://autarkaw.wordpress.com/2008/07/21/time-of-death-a-classic-ode-problem/


4. http://people.uncw.edu/lugo/mcp/DIFF_EQ/deproj/death/death.htm


5. http://mathforum.org/library/drmath/view/53409.html


6. http://www.scribd.com/doc/21514655/Newton-s-Law-of-Cooling-Finding-the-Time-of-Death-of-a-John-Doe

Numerical Problems for Practice - Current electricity

1. At room temperature (27 ^oC) resistance of a heating element is 100 ohm. What is the temperature of the element if the resistance is found to be 117 ohm. Given, temperature coeff. of resistance of the material is 1.70 x 10 ^{-14 o}C^-1


2. The ends of a resistance are connected to 19 cells in series, each of resistance 0.1 ohm. The current is found to be 2A. The number of cells is reduced to 15 and an extra resistance of 9.5 ohm is connected in series to the given resistance. The current becomes half. Find the given resistance and the emf of each cell.

Current electricity - Numerical problems

1. In a potentiometer arrangement a cell of emf 1.25 V gives a balance point at 35 cm length of the wire. If the cell is replaced by another cell, the balance point shifts to 63 cm. What is the emf of the second cell?

E1= 1.25 V

l1 = 35 cm

l2 = 63 cm

E1/E2 = l1/l2

E2 = l2E1/l1

E2 = 63 x 1.25/35

E2 = 2.25 V (Ans)

A Problem for Practice

A storage battery of emf 8 V and internal resistance 0.5 ohm is charged by 120V dc supply using a resistor 15.5 ohm in series. What is the terminal voltage of the battery during charging?

(Try to solve this problem and post your responses as comment to this post)

Hint: During charging; V = E +Ir

Bad Handwriting? Don't worry ! Here are some tips.

Bad hand writing is a cause of worry for many. They think that it cannot be improved easily.

But, you can make your hand writing attractive with a little care and following the three precautions

1. Keep the same size (Take care to write letters of same size)


2. Keep the same level (All letters should come in the same level.)


3. Keep the same inclination. (all letters must be equally inclined .. preferably forward)

Resistance and Resistivity

Simran Asked

"Two wires A and B of equal lengths,different cross-sectional areas and made of same metal a)name the property which is same for both the wires. b)name the property which is different for both the wires"

Answer:

Since both the wires are of same metal, the resistivity will be same for both whereas since the dimensions (Area of cross section here) are different, the resistance will be different

Potential Difference

Pawan Asked

"What is meant by potential difference?"

Answer:

"Potential Difference between two points is the difference in Potential between the two points and is equal to the work done per unit charge ion carrying a positive test charge from one point to another against the electric field and without any acceleration"

Limitations of Homogenity

Paraser asked

"What are the limitations of homogenity?"

The question is acutually"What are the limitations of dimensional analysis?"

The dimensional analysis is based on the principle of homogenity of dimensions. The question is already discussed earlier  HERE

Science Exhibition Ideas

The Science Exhibitions are nearing and almost every student is on search for new ideas for exhibits.

While developing your project for science exhibition, please keep in mind the following things.

• Identify a problem relevant to the society and try to offer a solution to it.
• Be innovative! Try to bring new ideas. (An idea can change your life ! .. as the ad says)
• Reduce cost ! It’s not the cost of the exhibit which determines its worth; but the utility and practicality counts.
• Show of your craftsmanship and perfection. Let your work look professional.

 

 

Read the complete set of guidelines given by NCERT here.

Geothermal Energy

p.tejaswini asked

"Why is geothermal energy an alternative source of nuclear energy?"

There is some problem with the doubt you asked. It is correct to say "Geothermal energy and Nuclear energy are alternative sources of energy"

Sun is the ultimate source of energy for earth. The energy of fuels, wind energy, water energy, food - all these are derived from sun. But Geothermal energy and nuclear energy are not derived from solar energy.

GeoThermal Energy Links for Reference

http://www.renewableenergyworld.com/rea/tech/geothermal-energy

http://www.geos.iitb.ac.in/geothermalindia/pubs/geoweb.htm

See a diagram of Geothermal plant

[caption id="" align="alignleft" width="525" caption="Geo Thermal Energy"][/caption]

The centre of the Earth is around 6000 degrees Celsius - easily hot enough to melt rock. Even a few kilometres down, the temperature can be over 250 degrees Celsius if the Earth's crust is thin. In general, the temperature rises one degree Celsius for every 30 - 50 metres you go down, but this does vary depending on location

In volcanic areas, molten rock can be very close to the surface. Sometimes we can use that heat.

Geothermal energy has been used for thousands of years in some countries for cooking and heating.

The name "geothermal" comes from two Greek words: "geo" means "Earth" and "thermal" means "heat".

Read More on Geothermal Energy Here

Educational Leadership linked to Student Achievement :: Study

A new study has claimed that good school leadership is critical to good education.
Researchers Kila vahlstrom and karen seashore Levy of the University of Minnesota College of Education and Human Development and Kenneth leithvood and Steven Anderson of the University of Toronto, have wide Implications for the understanding of how leadership affects learning across the United States.
"Leadership is important because it sets the conditions and the Expectations in the school that it will be excellent instruction and there will be a culture of ongoing learning for the Educators and for the students in the school," said vahlstrom.
The report Learning of Leadership: investigating the links to improved student learning, found that student achievement is higher in schools where principal share leadership with teachers and the community.
After finding was that Districts where levels of student learning are high, district leaders are March probably to emphasize goals and initiatives that reach beyond minimum state Expectations for student performance.
There are a few Challenges, though, such as - Stark lack of district support for Principal 'professional development, lack of regular contact between most principal and their district office and away from comprehensive Approaches to education reform in most States.
"So leadership absolutely makes a difference. I can not say that strongly enough, good leadership is critical to good education," said vahlstrom.

India Unveils A Portable Computing Device Worth Rs 1,600

Read the PIB release here http://www.pib.nic.in/release/release.asp?relid=63417

Today in New Delhi, union minister for Human Resource Development, Shri Kapil Sibal unveiled a low cost computing-cum-access device. The expected price of the showcased model is going to be around US$35 (approximately Rs 1,640) per unit, which is expected to gradually dip to about US$20 and will eventually to around US10$.

Since the ongoing reduction in cost and enhancing the capabilities require constant research and development, IIT Rajasthan and other technical institutions are setting up research teams to look into a wide range of potential issues in the course of achieving the ultimate goal in terms of price and quality.
The press release issued by the Ministry of HRD also states the primary aim, which is, to reach these low cost devices to students and teachers of all colleges and universities, which will enable them to gain access to high-quality digital content. As stated, the three cardinal principles of the Education Policy viz., access, equity and quality could be served well by providing connectivity to all educational institutions, providing low cost and affordable access cum computing devices to students and teachers and providing high quality e-content free of cost to all learners in the Country. National Mission on Education through ICT (NMEICT) encompasses all the three elements.

Connectivity to Universities and Colleges has already started. Nearly 8500 Colleges in the country have already been connected, high quality e-content in various subjects is being created and under the National Programme on Technology Enhanced Learning (NPTEL), nearly 500 web based and video courses are available and uploaded on “sakshat”, YouTube and NPTEL portals and another 1100 courses in various disciplines of engineering and science are getting generated in 4 quadrant approach.
The ministry started its efforts, subsequent to lukewarm response from known corporates in this sector, by holding discussions on this concept with a group of professors / experts at IISc, Bangalore, IIT Kanpur, IIT Kharagpur, IIT Madras and IIT Bombay. B.Tech and M.Tech students were guided to produce the motherboard for such low cost devices with ample room for upgrade / change in hardware components. One motherboard design was generated under Ministry’s guidance in the B.Tech project of a student at VIT, Vellore. The cost of bill of material worked to 47 $ at that point of time. The motherboard PCB was fabricated at IIT Kanpur. It could be seen that, by customizing the device to the needs of learners across the country, and utilizing the capabilities of CPU suitable for the purpose, it was possible to substantially reduce the prices of such access-cum-computing devices. Then, a wave of collaboration with such interested partners began.
Ever since, various teams have been moving back and forth independently, yet constantly interacting with the HRD Ministry and improving upon design parameters and customization guidance for Indian students. The efforts of some of the teams working with those design philosophies were presented today. The aim is to reach such devices to the students of colleges and Universities and to provide these institutions a host of choices of low cost access devices around Rs. 1500/- ($35) or less in near future.

Airbus launches global student contest for eco-efficient flight ideas

Farnborough: Students from Indian universities have an opportunity to compete in a global contest to develop eco-efficient air travel ideas launched by European aircraft giant Airbus at the Farnborough Air Show on Wednesday.Airbus launched its second bi-annual global students' contest "To shape the ...

Ex-LTTE rebels to apply for university courses

Colombo: Over 300 former Tamil Tiger rebels, currently under rehabilitation, will sit for an examination that would prepare them for higher education in the universities, the government said on Monday.Brigadier Sudantha Ranasinghe, commissioner general of rehabilitation, said 378 ex-LTTE (Liberation...

Indian-origin student wins New Zealand debate

Wellington: An Indian-origin student of New Zealand's Victoria University was part of a team that won a debating competition in which 100-odd varsities take part every year.Udayan Mukherjee was part of the three-member team of Victoria University which became the first New Zealand University to win ...

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Counselling starts at BHU

VARANASI: When it comes to taking admission to an undergraduate or postgraduate course in the city, nothing can match the hype and excitement of the Banaras Hindu University. The university came alive on Saturday with the beginning of the process of counselling and admissions.
While a number of students, including girls, could be seen visiting the campus along with their parents and guardians for admission to their favourite courses, the central office and various departments also bustled with admission-related activities.

 

Read more at http://timesofindia.indiatimes.com/city/varanasi/Counselling-starts-at-BHU/articleshow/6181680.cms

Common test to wean students away from coaching centres: Sibal

Disapproving of the growing influence of coaching centres that put engineering aspirants through a grind, making it difficult for them to concentrate on their senior secondary examinations, Human Resource Development Minister Kapil Sibal said on Saturday that curtailing the power of such institutions was one of the objectives of the recommendation for a common entrance test.

The coaching institutions “allow the rich and privileged to get their children admitted there and [these students] have a natural advantage [over financially weak students]. Coaching means focussing only on the IIT entrance examination without bothering about Class XII examinations. But this is not the best way to get the best students in the IIT programme,” the Minister said speaking to journalists after the 56th annual convocation of IIT-Kharagpur,

The report of the committee, looking into the proposal for a single-test for engineering admissions, was expected by the beginning of August. “I do not want the students to sit for 20 to 30 examinations. We must reduce the pressure on them and we shall do whatever it takes to lessen the pressure. Many proposals may come our way but we will choose the best for the system that allows the institutions not to depend entirely on one examination for the admission process.”

 

Read More at http://www.thehindu.com/news/states/other-states/article520920.ece?homepage=true

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123MyBlog offers Free blog sites (Not Just a Blog) for anyone who like to blog to the world.

There are hundreds of excellent themes to choose from.

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Start Blogging Free!

Welcome to 123myblog.com

Signup Now

123MyBlog offers Free blog sites (Not Just a Blog) for anyone who like to blog to the world.

There are hundreds of excellent themes to choose from.

Serious bloggers can earn online from advertisement from adsense, adbrite, infolinks, kontera and the like. (There will be a watch out period of one month before the user is guided through Eard from Ads procedure)

Signup Now

Do You know? You can prevent most of the virus attacks by logging in as a restricted user !

The viruses get more privileges and access to system files when you are logged in as admin user. So, it is a good idea to create a limited user account for your pc and use it to access internet and for other works where admin powers are not required. Login as admin user only when it is absolutely necessary. As a further measure, you may disconnect internet when you are logged in as admin user.

Another important step is to disable auto run for CDs and pen drives (All removable media), so that the files are not opened automatically until you scan them with antivirus software.

 

Happy surfing !!!

PERFECT BOSSS..

I got the following by email ….

There were about 70 scientists working on a very hectic project. All of  them were really  frustrated due to the pressure of work and the  demands of their boss but everyone was loyal  to him and did not think of quitting the job. 

One day, one scientist came to his boss and told  him - Sir, I have promised to my children that I
will take them to the exhibition going on in our township. So I want to leave the office at 5 30 pm.
His boss replied "OK, You're permitted to leave the office early today"
The Scientist started working. He continued his work after lunch. As usual he got involved to such  an extent that he looked at his watch when he felt he was close to completion. The time was 8.30 PM. Suddenly he remembered of  the promise he had given to his children. He looked for his boss, He was not there. Having told him in the morning itself, he closed everything and left for home. Deep within himself, he was feeling guilty for having disappointed his children. He reached home.
Children were not there. His wife alone was sitting in the hall and reading magazines.
The situation was explosive, any talk would boomerang on him. His wife asked him "Would you
like to have coffee or shall I straight away serve dinner if you are hungry.
The man replied "If you would like to have coffee, i too will have but what about Children ??"
Wife replied "You don't know ?? Your manager came here at 5.15 PM and has taken the children
to the exhibition "
What had really happened was ...

 
The boss who granted him permission was observing him working seriously at 5.00 PM.
He thought to himself, this person will not leave the work, but if he has promised his children they should enjoy the visit to exhibition.
So he took the lead in taking them to exhibition The boss does not have to do it every time. But
once it is done, loyalty is established.
That is why all the scientists at Thumba continued to work under their boss even though the stress was tremendous.
By the way , can you hazard a guess as to who the boss was..?
GO BELOW FOR ANSWER

He was none other than

Dr. APJ Abdul Kalam, Former-President of India . . .

"Confidence never comes if we have all the answers,
But it comes when we are ready for all the questions."

 

BUT I AM MORE INTERESTED TO KNOW WHO THE DEDICATED SCIENTIST WAS

PERFECT BOSSS..

I got the following by email ….

There were about 70 scientists working on a very hectic project. All of  them were really  frustrated due to the pressure of work and the  demands of their boss but everyone was loyal  to him and did not think of quitting the job. 

One day, one scientist came to his boss and told  him - Sir, I have promised to my children that I
will take them to the exhibition going on in our township. So I want to leave the office at 5 30 pm.
His boss replied "OK, You're permitted to leave the office early today"
The Scientist started working. He continued his work after lunch. As usual he got involved to such  an extent that he looked at his watch when he felt he was close to completion. The time was 8.30 PM. Suddenly he remembered of  the promise he had given to his children. He looked for his boss, He was not there. Having told him in the morning itself, he closed everything and left for home. Deep within himself, he was feeling guilty for having disappointed his children. He reached home.
Children were not there. His wife alone was sitting in the hall and reading magazines.
The situation was explosive, any talk would boomerang on him. His wife asked him "Would you
like to have coffee or shall I straight away serve dinner if you are hungry.
The man replied "If you would like to have coffee, i too will have but what about Children ??"
Wife replied "You don't know ?? Your manager came here at 5.15 PM and has taken the children
to the exhibition "
What had really happened was ...

 

The boss who granted him permission was observing him working seriously at 5.00 PM.
He thought to himself, this person will not leave the work, but if he has promised his children they should enjoy the visit to exhibition.
So he took the lead in taking them to exhibition The boss does not have to do it every time. But
once it is done, loyalty is established.
That is why all the scientists at Thumba continued to work under their boss even though the stress was tremendous.
By the way , can you hazard a guess as to who the boss was..?
GO BELOW FOR ANSWER

He was none other than

Dr. APJ Abdul Kalam, Former-President of India . . .

"Confidence never comes if we have all the answers,
But it comes when we are ready for all the questions."

 

BUT I AM MORE INTERESTED TO KNOW WHO THE DEDICATED SCIENTIST WAS

LIGHT –REFLECTION AND REFRACTION QUESTIONS TO PRACTICE

LIGHT –REFLECTION AND REFRACTION

QUESTIONS TO PRACTICE

1. What are the differences between real image and virtual image?

2. The radius of curvature of a concave mirror is -46cm.What is its focal length?

3. How will you identify a plane mirror, a concave mirror and a convex mirror without touching their surface?

4. Which mirror has a wider field of view? Why?

5. What happens to a ray of light when it travels from a rarer medium to a denser medium?

6. What will be the signs of u, v and f for a convex lens as per sign convention?

7. State Snell’s law of refraction?

8. A lens always forms a diminished, erect and virtual image .Identify the nature of the lens?

9. Where should an object be placed so that a real and inverted image of the same size is formed using a convex lens?

10. How is the power of a lens related to its focal length?

11. What is the S I unit of power of a lens? Define.

12. Two lenses having power P1 and P2 are placed in contact. What is the net power of the combination?

13. Two lenses of powers 4D and -5D are kept in contact. Find the focal length of the combination. What is the nature of the combination?

14. What do you understand by the term refractive index?

15. The image of our face is viewed in and out of the curved surface of a spoon. What change in the image is observed? How will you explain this?

16. You should not look at the sun directly or even into a mirror reflecting the light from the sun. Justify.

17. You need an erect and enlarged image of on object on a mirror. Which mirror would you choose?

18. You need to get an image of the size as that of the object using a lens. What is the suitable lens to be used?

19. The image of an object at a distance of 20 cm from a mirror is formed at the object itself.

1) Identify the mirror 2) The nature of the image

3) size of the image 4) the focal length of the mirror

5) radius of curvature of the mirror

Draw the corresponding ray diagram.

20. Draw a ray diagram to show the formation of the image of an object placed at the centre of curvature of a concave mirror.

21. A convex mirror used on an automobile has radius of curvature of 2 m .If a car is located at 4 m from the mirror, find the position nature and size of the image

22. Why is convex mirror preferred to be used as a driver’s rear-view mirror?

23. For what position of an object, a virtual image is formed by a convex lens? Draw a ray diagram to show the formation of a virtual image by a convex lens. What are the other characteristics of the image?

24. Why is a concave lens is called diverging lens, whereas a convex lens a converging lens? Explain with the help of ray diagrams.

25. Why the apparent depth of a swimming pool is less than its real depth? On what factors does the difference between the two depend?

26. Two lenses having power of 2.0D and 0.25D are combined together. What is the

(a) net power of combination?

(b) focal length of the combination?

27. Give two uses of convex lens.

28. Give two uses of convex mirrors

29. Give two uses of concave mirror.

30. Give two uses of concave lens

31. Give two uses of plane mirror.

32. Show the path of a ray of light through a rectangular glass slab. Label incident ray, refracted ray, emergent ray, the angle of incidence and angle of emergence and lateral displacement. Why is angle of incidence equal to the angle of emergence?

33. Drawing ray diagrams for an object at infinity and by using the new sign convention show that the focal length of a concave mirror is negative and that of convex mirror is positive.

34. State three rules for drawing geometric images in concave lens.

28. A reflected ray of light makes an angle of 900 with the incident ray of light. What are the angle of incidence and the angle of reflection? Draw a diagram to illustrate these rays.

29. State the laws of refraction.

30. An object 4cm high is placed 15cm away from a concave lens of focal length 10cm. Draw a ray diagram and find the position, size and nature of the image formed.

35. An object is kept in front of a concave mirror of focal length 20cm.The image formed is three times the size of the object. Calculate the two possible distances of the object from the mirror.

36. An object 0.4m high is placed at a distance of 0.8m from a concave mirror of radius curvature 0.4m. Find the position, nature and size of the image formed?

37. Two thin converging lenses of focal length 15cm and 30cm are held in contact with each other. Calculate the power and focal length of combination.

38. Find the position of an object which when placed in front of a concave mirror of focal length 20cm, produces a virtual image, which is twice the size of the object.

39. Draw a ray diagram to show the formation of an object placed between the pole and focus of a concave mirror.

40. What is a lens? Distinguish between a convex and concave lens.

41. What do you understand by the power of a lens? Define magnification in case of spherical mirror and lens. Mention the new Cartesian sign convention applicable to in this case.

42. Draw a ray diagram to show the formation of the image of an object placed between optical centre and focus of a convex lens.

43. You are required to obtain an erect image of an object placed in front of a concave mirror of focal length 15cm.What should be the approximate distance of the object from the pole of the mirror? What is the nature of the image? Is the image larger of smaller in size than the object? Draw a ray diagram to show the formation of image.

44. An object of size 5cm is placed at a distance of 25cm from the pole of a concave mirror of radius of curvature 30cm.Calculate the distance and size of the image so formed. What will be the nature of the image?

45. An object of size 3cm is placed at a distance of 15cm from a convex lens of focal length 10cm.Calculate the distance and size of the image so formed. What will be the nature of the image?

46. Determine the speed of light in glass which has refractive index of 1.5, if the speed of light in vacuum is 3x108m/s.

47. A 1cm high image is obtained on a screen a t a distance of 20cm from a convex lens of focal length 10cm.What is the size the object?

48. The radius of curvature of a convex mirror is used on a moving automobile is 2.0 m. A truck is coming behind it at a constant distance of 3.5 m. Calculate (1) the position, and (2) the size of image relative to the size of the truck. What will be the nature of the image?

49. (a) Draw a ray diagram to show passage of two rays of light through a rectangular slab of glass, when the angle of incidence is zero in one case and a littler less than 900 in the other case.

50. A transparent medium A floats on another transparent medium B .When a ray of light travels obliquely from A into B the reflected ray bends away from the normal. Which of the media A and B is optically denser and why?

51. Where will the image is formed by a convex mirror if the object is placed between infinity and the pole of the mirror?

52. A convex lens has a focal length of 50cm. Calculate its power.

53. IDENTIFY THE LENS/MIRROR

i) Focal length positive

ii) Focal length negative

iii) Power positive

iv) Power negative

v) Forms virtual image always magnified

vi) Forms only diminished virtual images

vii) Magnification always positive

viii) Magnification always less than one

ix) Can produce image of the same size

x) Forms real point sized image

xi) Forms virtual point sized image

xii) Used as shaving mirror

xiii) Used as rear view mirror

xiv) Have wide field of view

xv) Converges the incident rays

xvi) Diverges the incident rays

Electricity Practice Questions for CBSE

1. Define electric potential difference?

2. Why is an ammeter connected in series in a circuit?

3. Why is a voltmeter connected in parallel in a circuit?

4. State the law that governs the strength of the current passing through a metallic conductor when a p.d is applied across its end. Illustrate this law graphically?

5. State the law which governs the amount of heat produced in a metallic conductor when current is passed through it for a given time. Express this law mathematically?

6. Define resistance. What are the factors on which it depends?

7. A copper wire of resitivity P is stretched to reduce its diameter to half its previous value. What is the new resistivity?

8. Define the S I unit of electric current and potential difference.

9. Derive expressions for equivalent resistance of resistors connected in

a. series combination

b. parallel combination

10. What is an electric fuse? Explain its function.

11. Explain, how the heating effect of electric current is made use in the functioning of an electric bulb?

12. State the relation between the commercial and SI unit of electric energy.

13. Write the advantages of connecting electrical appliances in parallel and disadvantages of connecting them in series in a household circuit.

14. Why is tungsten used almost exclusively for making the filaments of electric lamps?

15. A piece of wire is redrawn by pulling it until its length is doubled .Compare the new resistance with the original value.

16. An electric geyser has rating 2000 w, 220 v marked on it. What should be the minimum rating in whole number of a fuse wire that may be required for safe use with the geyser?

17. Three resistors each of resistance 10 ohm are connected, in turn, to obtain a. minimum resistance b. Maximum resistance. Compute

a) The effective resistance in each case

b) The ratio of minimum to maximum resistance so obtained.

18. Two resistors of resistance 2 ohms and 4 ohms are, in turn connected

a) In series

b) In parallel to a given battery for same interval.

Compute the ratio of the total quantity of heat produced in the combination in the two cases.

19. Two metallic wires A and B are connected in parallel. Wire A has length L and radius R wire B has a length 2L and radius 2r. Compute the ratio of the total resistance of parallel combination and resistance of wire A.

20. In a house three bulb of 100w each are lighted for 4 hours daily and six tube lights of 20w each are lighted for 5 hours daily and a refrigerator of 400w is worked for 10 hours daily for a month of 30 days. Calculate the electricity bill if the cost of one unit is Rs 4.00.

21. Three resistors of 4ohms, 6ohms and 12 ohms are connected in parallel. The combination of above resistors is connected in series to a resistance of 2 ohms and then to a battery of 6 volts. Draw a circuit diagram and calculate

a) Current in main circuit

b) Current flowing through each of the resistors in parallel

c) P.d and the power used by the 2 ohm resistor.

22. Two lamps, one rated 100 W at 220 V and the other 60W at 220 V, are connected in Parallel to a 220 volt supply. What current is drawn from the supply line?

Class X Physics QUESTION BANK(Magnetic Effects of Current)

One mark Questions:
1. How can you show that the magnetic field produced by a given electric current in the wire decreases as the distance from the wire decreases?
2. What is the advantage of the third wire of earth connection in domestic appliances?
3. What constitutes the field of a magnet?
4. What is short-circuiting in an electric supply?
5. What will be the frequency of an alternating current if its direction changes after every 0.01s?
6. An alternating electric current has a frequency of 50 Hz. How many times does it change its direction in 1s?
7. How is the strength of the magnetic field at a point near a wire related to the strength of the electric current flowing in the wire?
8. How can it be shown that a magnetic field exists around a wire through which a direct current is passing?
9. On what effect of an electric current does an electromagnet work?
10. What is the direction of magnetic field at the centre of a circular coil carrying current in anticlockwise direction?

 Two Mark Questions
1. With the help of a neat-diagram, describe how you can generate induced current in a circuit.
2. What is meant by the term “Magnetic field Lines”? List two properties of magnetic field lines.
3. Write the rule which determines the direction of magnetic field developed around a straight conductor when current is passed through the conductor.
4. State the rule to determine the direction of magnetic field produced around a current carrying conductor.
5. On which factors does the force experienced by a current carrying conductor placed in a uniform magnetic field depend?
6. State Fleming’s right-hand Rule.
7. Why is series arrangement not used for domestic circuits?
8. Differentiate between electric force and magnetic forces.
9. How does AC differ from DC? What are the advantages and disadvantages of AC over DC?
10. Draw the magnetic field due to a current carrying circular coil. State the clock rule to find the polarities of the faces of the coil.

Three Mark Questions
1. Draw the pattern of field lined due to a solenoid carrying electric current. Mark the north and the south poles in the diagram.
2. Draw the pattern of lines of force due to a magnetic field through and around a current carrying loop of wire. How would the strength of the magnetic field produced at the centre of the circular loop be affected if (i) the strength of the current passing through this loop is doubled? (ii) the radius of the loop is reduced to half of the original radius?
3. Draw the pattern lines of force due to a magnetic field associated with a current carrying conductor. State how the magnetic field produced changes (i) with an increase in current in the conductor and (ii) the distance from the conductor.
4. Draw the pattern of field lines due to a bar magnet. Mention any two properties of the magnetic field lines.
5. How does the strength of the magnetic field at the centre of a circular coil of wire depend on: (i) the radius of the coil? (ii) the number of turns of the wire? (iii) the strength of the current flowing in the coil?
6. The flow of a current in a circular loop of a wire creates a magnetic field at its centre. How can existence of the field be detected? State the rule which helps to predict the direction of this magnetic field.
7. What are the factors on which the strength of magnetic field produced by current-carrying solenoid depends?
8. A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is: (i) pushed into the coil with north pole entering first (ii) pulled out of the coil (iii) held stationary inside the coil?
9. Explain what is short-circuiting and overloading in an electric supply.
10. What are magnetic field lines? How is the direction of a magnetic field at a point determined? Mention two important properties of the magnetic field lines.

Five Mark Questions:
1. (a) Suggest an activity to show the pattern of magnetic field lines, when you are provided with a bar magnet, a cardboard piece and iron filings.(b)Draw a rough sketch of the field lines which you will observe.
2. (a) What is an electromagnet? What does it consists of? (b) Name one material in each case used to make a (i) permanent magnet (ii) temporary magnet. (c) Describe an activity to show how can you make an electromagnet in your school lab?
3. State Fleming’s left-hand rule. With a labeled diagram, describe the working of an electric motor. What is the function of split-ring Commutator in a motor?
4. State Fleming’s right-hand rule. With a labeled diagram, describe the working of an AC electric generator.
5. Draw the lines of force of the magnetic field through and around (a)single loop of wire carrying current, (b) a solenoid carrying electric current.
6. Why is pure iron not used for making permanent magnets? Name one material used for making permanent magnets. Describe how permanent magnets are made electrically. State two examples of electrical appliances made by using permanent magnets.
7. (a)Draw a schematic labeled diagram of a domestic wiring circuit which includes (i)a main fuse (ii) a power meter (iii)one light point (iv) a power plug.(b) Why is it necessary to connect an earth wire to electric appliances having metallic covers?
8. (a)What are magnetic field lines? How is the direction of a magnetic field at a point determined? (b) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks. (c) List any three properties of magnetic field lines.
9. What is an electric motor? With the help of a diagram, describe the working of an electric motor.
10. What are magnetic field lines? Write their characteristics. Draw the magnetic field lines due to a current flowing in a circular coil.
11. Explain the principle, construction and working of an electric motor.
12. Explain with labeled diagram, the principle, construction and working of an electric generator.
13. (a ). What is an electromagnet ?
(b). List any of its two uses.
(c ). Draw a labeled diagram to show how an electromagnet is made.
(d ). What is the purpose of the soft iron core used in making an electromagnet ?

Numerical:
1. The mains power supply of a house is through a 5-A fuse. How many 100-W bulbs can be used in this house at the correct voltage?
2. A wire 10 cm long and carrying a current of 1.5 A is held in a uniform magnetic field in which B=10-3 T. Calculate the force on the wire if it is held perpendicular to the lines of the magnetic field.
3. A current of 10 A flows in a circular coil of 1000 turns and radius 0.1 m. Find the magnitude of the magnetic field at the centre of the coil.
4. At what distance from a straight conductor carrying a current of 2.8 A, will the magnetic induction be 2.8x10-5 T?
5. Find the strength of the current which will produce a magnetic field of 10-4 T at the centre of a coil of mean radius 0.10 m. The coil comprises 20 turns.
6. A 0.4 m wire, stretched horizontally, carries an electric current of 15 A from East to West, in a magnetic field whose magnetic field intensity is 0.1 N/Am, directed vertically downwards. What is (a) the magnitude of the magnetic deflecting force on the wire, and (b) its direction?

Class X Physics QUESTION BANK(Magnetic Effects of Current)

One mark Questions:
1. How can you show that the magnetic field produced by a given electric current in the wire decreases as the distance from the wire decreases?
2. What is the advantage of the third wire of earth connection in domestic appliances?
3. What constitutes the field of a magnet?
4. What is short-circuiting in an electric supply?
5. What will be the frequency of an alternating current if its direction changes after every 0.01s?
6. An alternating electric current has a frequency of 50 Hz. How many times does it change its direction in 1s?
7. How is the strength of the magnetic field at a point near a wire related to the strength of the electric current flowing in the wire?
8. How can it be shown that a magnetic field exists around a wire through which a direct current is passing?
9. On what effect of an electric current does an electromagnet work?
10. What is the direction of magnetic field at the centre of a circular coil carrying current in anticlockwise direction?

Two Mark Questions
1. With the help of a neat-diagram, describe how you can generate induced current in a circuit.
2. What is meant by the term “Magnetic field Lines”? List two properties of magnetic field lines.
3. Write the rule which determines the direction of magnetic field developed around a straight conductor when current is passed through the conductor.
4. State the rule to determine the direction of magnetic field produced around a current carrying conductor.
5. On which factors does the force experienced by a current carrying conductor placed in a uniform magnetic field depend?
6. State Fleming’s right-hand Rule.
7. Why is series arrangement not used for domestic circuits?
8. Differentiate between electric force and magnetic forces.
9. How does AC differ from DC? What are the advantages and disadvantages of AC over DC?
10. Draw the magnetic field due to a current carrying circular coil. State the clock rule to find the polarities of the faces of the coil.

Three Mark Questions
1. Draw the pattern of field lined due to a solenoid carrying electric current. Mark the north and the south poles in the diagram.
2. Draw the pattern of lines of force due to a magnetic field through and around a current carrying loop of wire. How would the strength of the magnetic field produced at the centre of the circular loop be affected if (i) the strength of the current passing through this loop is doubled? (ii) the radius of the loop is reduced to half of the original radius?
3. Draw the pattern lines of force due to a magnetic field associated with a current carrying conductor. State how the magnetic field produced changes (i) with an increase in current in the conductor and (ii) the distance from the conductor.
4. Draw the pattern of field lines due to a bar magnet. Mention any two properties of the magnetic field lines.
5. How does the strength of the magnetic field at the centre of a circular coil of wire depend on: (i) the radius of the coil? (ii) the number of turns of the wire? (iii) the strength of the current flowing in the coil?
6. The flow of a current in a circular loop of a wire creates a magnetic field at its centre. How can existence of the field be detected? State the rule which helps to predict the direction of this magnetic field.
7. What are the factors on which the strength of magnetic field produced by current-carrying solenoid depends?
8. A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is: (i) pushed into the coil with north pole entering first (ii) pulled out of the coil (iii) held stationary inside the coil?
9. Explain what is short-circuiting and overloading in an electric supply.
10. What are magnetic field lines? How is the direction of a magnetic field at a point determined? Mention two important properties of the magnetic field lines.

Five Mark Questions:
1. (a) Suggest an activity to show the pattern of magnetic field lines, when you are provided with a bar magnet, a cardboard piece and iron filings.(b)Draw a rough sketch of the field lines which you will observe.
2. (a) What is an electromagnet? What does it consists of? (b) Name one material in each case used to make a (i) permanent magnet (ii) temporary magnet. (c) Describe an activity to show how can you make an electromagnet in your school lab?
3. State Fleming’s left-hand rule. With a labeled diagram, describe the working of an electric motor. What is the function of split-ring Commutator in a motor?
4. State Fleming’s right-hand rule. With a labeled diagram, describe the working of an AC electric generator.
5. Draw the lines of force of the magnetic field through and around (a)single loop of wire carrying current, (b) a solenoid carrying electric current.
6. Why is pure iron not used for making permanent magnets? Name one material used for making permanent magnets. Describe how permanent magnets are made electrically. State two examples of electrical appliances made by using permanent magnets.
7. (a)Draw a schematic labeled diagram of a domestic wiring circuit which includes (i)a main fuse (ii) a power meter (iii)one light point (iv) a power plug.(b) Why is it necessary to connect an earth wire to electric appliances having metallic covers?
8. (a)What are magnetic field lines? How is the direction of a magnetic field at a point determined? (b) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks. (c) List any three properties of magnetic field lines.
9. What is an electric motor? With the help of a diagram, describe the working of an electric motor.
10. What are magnetic field lines? Write their characteristics. Draw the magnetic field lines due to a current flowing in a circular coil.
11. Explain the principle, construction and working of an electric motor.
12. Explain with labeled diagram, the principle, construction and working of an electric generator.
13. (a ). What is an electromagnet ?
(b). List any of its two uses.
(c ). Draw a labeled diagram to show how an electromagnet is made.
(d ). What is the purpose of the soft iron core used in making an electromagnet ?

Numerical:
1. The mains power supply of a house is through a 5-A fuse. How many 100-W bulbs can be used in this house at the correct voltage?
2. A wire 10 cm long and carrying a current of 1.5 A is held in a uniform magnetic field in which B=10-3 T. Calculate the force on the wire if it is held perpendicular to the lines of the magnetic field.
3. A current of 10 A flows in a circular coil of 1000 turns and radius 0.1 m. Find the magnitude of the magnetic field at the centre of the coil.
4. At what distance from a straight conductor carrying a current of 2.8 A, will the magnetic induction be 2.8x10-5 T?
5. Find the strength of the current which will produce a magnetic field of 10-4 T at the centre of a coil of mean radius 0.10 m. The coil comprises 20 turns.
6. A 0.4 m wire, stretched horizontally, carries an electric current of 15 A from East to West, in a magnetic field whose magnetic field intensity is 0.1 N/Am, directed vertically downwards. What is (a) the magnitude of the magnetic deflecting force on the wire, and (b) its direction?

QUESTION BANK Class X Physics (Electricity)

Very short answer questions (1 mark)
1. Give the unit of (a) Charge (b) Current
2. Define current
3. Name the unit of (a) electrical resistance (b) resistivity
4. Define One Ohm
5. Define Resistivity
6. What is the resistance of a torch bulb rated at 2.5 V and 500 mA?
7. Two resistances of each 2 ohm are connected in parallel. Find their equalent resistance.
8. On what factors does the resistivity of a material depend?
9. Plot a graph between the Potential difference V and current I through a conductor
10. What happens to the resistance of the circuit if the current through it is doubled?

Short answer questions (2 marks)
1. Two wires of same material are having length L and 2L. Compare their resistance and resistivity.
2. Why are coils of electric toaster and electric iron made of an alloy rather then a pure metal?
3. Two wires are of same length and radius but one of them is copper and the other is of iron. Which will have more resistance? (Given the resistivity of copper = 1.62 x 10 -8 ohm meter and resistivity of iron = 10 x 10-8 ohm meter.
4. Define 1KWh. Give the relation between 1kwh and Joule.
5. State which has a higher resistance. A 50W or 25W lamp. Also find the ratio of their resistances.
6. A wire of resistance 5 Ohm is spent in the form of closed circle. What is the resistance between 2 points at the ends of any diameter of the circle?
7. Calculate the amount of charge that would flow in one hour through the element of an electric iron drawing a current of 0.4 amps.
8. A electric toaster of resistance 20 Ohm takes a current of 5A. Calculate the heat developed in 30 s.
9. A bulb is rated at 5V, 100mA. Calculate its (1) Power (2) Resistance
10. Name two special characteristics of a heater coil.

Short answer questions (3 marks)
1. Define resistance and resistivity. Give the relation between them. Explain the dependence of resistance on temperature.
2. With the help of neat circuit, derive the expression for the equalent resistance of 3 resistances connected in series.
3. With the help of neat circuit, derive the expression for the equivalent resistance of 3 resistances connected in parallel
4. (a ) Draw the circuit consisting of a battery of five 2V cells, 5ohm resistor, 10 ohm resistor, 15 ohm resistor and a plug key. All connected in series (b) Calculate the current passing through the above circuit when key is closed.
5. Two identical resistors each of resistance 2 Ohm are connected in turn (1) in series (2) in parallel to a battery of 12 V. Calculate the ratio of power consumed in two cases.
6. A piece of wire is redrawn by pulling it until its length is tripled. Compare the new resistance with the original value.
7. An electric kettle is rated 500W, 200V. IT is used to heat 400 gm of water for 30 secs. Assuming the voltage to be 220V calculate the rise in temperature of water. Specific heat capacity of water is 4200 J/Kg ºC.
8. In an experiment the current flowing through a resistor and potential difference across it are measured. The values are given below. Show that these values confirm Ohm’s Law and also find the resistance of the resistor.
I (ampere) I(ampere) 1.0 1.0 2 1.5 2.0 2.0 2.5 2.5 3.0 3.0
V (volt) V(volt) 4.0 4.0 6.0 6.0 8.0 8.0 10.0 10.0 12.0 12.0

9. A heater draws 1100 W at 220V. (a) Find the resistance of the heater (b) Calculate the energy in KWh consumed in a week if the heater is used daily for 4 hours.

Long Answer questions (5 marks)
1. State Ohms law with a neat circuit. Explain how this law can be verified and also plot the expected v-I graph.
2. (a) Differentiate resistance and resistivity
(b) the ratio of resistivities of two materials a and b is 1:2, ratio of their length is 3:4 and if the ratio of radii is 2:3 find the ratio of resistance of a and b.

Maharashtra Government Has Increased MBA Seats By 53%

Maharashtra government has decided to increase seats for management programs in the state by 53%. This news has been received well by management aspirants since colleges now will be authorized to start a second shift for MBA and Masters in Management Studies programs. In 2010--2011, the number of seats will be 33,045 and apart from management, there are 88,370 engineering seats, 8,513 in pharmacy and 7,138 MCA seats in the state. A Directorate of Technical Education (DTE) spokesperson said, “A management degree is highly popular and sought-after. To meet the ever-increasing demand, the All India Council for Technical Education (AICTE) has approved second shifts for management programmes this year. Further, the AICTE has also allowed new colleges to have 120 students in their first batch, instead of 60, which used to be the earlier rule. This has led to a sizeable increase in the total number of seats”.

IGNOU Has Set up New Professional Courses in Collaboration with NIIT

IGNOU has introduced new professional programs like An Executive MBA, eight new finishing school courses and a B.Sc. IT course. These courses have been designed in tandem with the dynamic business needs and for job-hunting purposes. IGNOU Vice Chancellor Mr. V.N. Rajasekharan Pillai and NIIT Chairman Rajendra S. Pawar have signed the partnership agreement on July 10, 2010. These programs will be launched in partnership with NIIT. Mr. V.N. Rajasekharan Pillai, IGNOU Vice Chancellor said, "These courses will go a way ahead in realizing our aim of inclusive education. This is the decade of innovation and we have to train more than 500 million youth in India in this time.” NIIT Chairman, Mr. Pawar said, "These courses are for students from all walks of life. Not all may score high in exams; these courses give an opportunity to them as well.”

PTE Has Been Approved as English Tester by Business Schools

Harvard Business School and other leading B-schools like Stanford, Yale, INSEAD, ISB, Hyderabad and UK Border Agency have approved PTE Academic scores. PTE Academic is an international computer-based academic English language test, developed by Pearson group. Graduate Management Admission Council (GMAC), the administrator of the GMAT test, has sanctioned PTE Academic, an English language test structured to assess the proficiency of a non-native English speaker to comprehend the English language instruction programs at University level. Mr. John K Philip, Regional Director (SAARC Countries), Pearson Language Tests, said, “The fast- growing acceptance of this test, which is endorsed by GMAC, is testimony to the fact that it setting a new standard in academic English language testing".

Mechanical Engineering Gains Popularity Among Engineering Aspirants

The Central Admission Committee has declared that more & more engineering aspirants are opting for mechanical engineering over other engineering streams. The reason behind the increasing popularity of mechanical engineering as a career option is its impeccable placement record in the last two years. In 2009, companies selected 70 students of mechanical engineering stream from LD Engineering Institute followed by Electrical and Electronics & Communications engineering streams. This year also 51 mechanical engineers have been placed in reputed companies and 21 each from EC and Electrical. Prof KB Bhoyania, Placement officer at LD Engineering College, said, “It has been the trend since the last two years that the highest placement goes to students having taken up mechanical engineering."

ELECTROSTATICS TEST PAPER FOR CLASS XII

 

1. What orientation of an electric dipole in a uniform electric field corresponds to its stable equilibrium?

2. What is the area of the plates of a parallel plate capacitor of capacitance 2F and with separation between plates 0.5 cm?

3. What is the work done in carrying a point charge 10 nC between two points separated by a distance 5 cm on an equipotential surface?

4. A parallel plate capacitor is made by stacking ‘n’ equally spaced plates connected alternatively. If the capacitance between any two plates is ‘C’, determine the resultant capacitance of the combination

5. Calculate the coulomb force between two a particles separated by a distance of 3.2 x 10^-15 m

6. Draw graph showing variation of electric field with distance for a uniformly charged metallic sphere.

7. An electron and proton are free to move in an electric field. Which one will have greater acceleration? Why?

8. Sketch two equipotential surfaces for (a) a point charge. (b) between two plane sheets of charge.

9. Show that the work done in rotating an electric dipole of dipole moment p in a uniform electric field E by an angle θ from the equilibrium postition W = PE(1-cos θ)

10. The given graph shows the variation of charge ‘q’ verses potential difference for two capacitors C1 and C2 .The capacitors have same plate separation, but the plate area of C2 is double that of C1.Identify the line in the graph corresponding to C1 & C2 and why?

11. Derive an expression for the torque acting on an electric dipole placed in a uniform electric field.

12. Derive an expression for the capacitance of a parallel plate capacitor.

13. You are given three capacitors of value 2μF, 3μF, 6μF. How will you connect them to a resultant capacity of 4μF?

14. Two equally charged identical metal spheres A and B repel each other with a force of 2·0 x 10^-5 N. Another identical uncharged sphere C is touched to A and then placed at the mid point between A and B. What is the net force on C?

15. A dielectric slab of thickness t introduced between the plates of a parallel plate capacitor separated by a distance d. (t < d). Derive an expression for the capacitance of the capacitor

16. Describe the principle construction and working of a Van de graff Generator with the help of a neat labeled diagram.

17. Use Gauss theorem to derive an expression for the electric field at a point due to

a. an infinite plane sheet of charge of uniform charge density σ

b. a thin infinitely long straight line  of charge of uniform charge density λ

************************

Why the current through a conducting wire and a resistor are the same though the resistor has a greater resistance?

When a resistor is connected to a source using conducting wires, both are in series. The current through the wire as well as the resistor is determined by the total resistance of the circuit according to the relation

V = IR

Similarly, when a current is passed through a heating element, the connecting wires are not heated; only the heating element gets heated up since when a constant current is passed, the heat produced is directly proportional to resistance. The current in a series combination cannot change from component to component as current is the rate of flow of charge and the charge supplied by the source must be flowing through all the components connected in series; there is no creation or loss of charge along the circuit.

Question waiting to be answered.

The following questions are waiting to get an answer. You can also try answering them through the comment system

1. what happens when a unchargedbody comes i contact with a charged body?
2. Twelve wires, each of resistance r,are connected to form a skeleton cube. Find the equivalent resistance between the two diagonally opposite corners of the cube.
3. Twelve wires, each of resistance r,are connected to form a skeleton cube. Find the equivalent resistance between the two corners of the same edge of the cube
4. Please explain me how to calculate tension in a catenary wire at different points (without using calculus)
5. In vectors, what is i^ + j^+ k^?
6. From where does charges arise in electrons and protons?
7. What is the difference between viscosity and elasticity?
8. A 3-dimensional space consists of how many planes?
9. A hyperspace consists of how many planes?
10. In series connection of resistors, does the current remains unchanged?
11. Why does Nichrome not used as the filament in an incandescent lamp?
12. How to check the correctness of equation s=u+0.5a(2n-1) using dimensional analysis?(Please describe)
13. In law of conservation of linear momentum derivation,why force acting on body B by A is taken as product of mass and acceleration of "B" and not "A" instead of "B"?

Government Has Decided to Introduce Two IIITs In The Northeast

The Central government is planning to set up two new Indian Institutes of Information Technology in the northeastern region. While addressing the All India Editors conference, Ms. Purandeswari, Minister of State for Human Resource Development said, "The locations are being worked out." The minister informed that 44 new colleges and six engineering colleges will be launched in northeastern states. Ms. Purandeswari said, "Out of the 10 new National Institutes of Technology (NIT) proposed to be opened in the country during the 11th Five Year Plan, 6 NITs are proposed to be opened in Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland and Sikkim."

Physics doubts from Class XI student

1. How to check the correctness of equation s=u+0.5a(2n-1) using dimensional analysis?(Please describe)
2. In law of conservation of linear momentum derivation,why force acting on body B by A is taken as product of mass and acceleration of "B" and not "A" instead of "B"?

 

Answer

1. The accuracy is checked as usual, but remember that the quantity on LHS is not displacement, but displacement in one second which should have the dimension same as speed or velocity. It can be shown that each of the term on RHS has the dimensions LT^-1
2. The force acting on B will be the product of mass of B and the acceleration of B, as force exerted by A is the cause which produced the acceleration. Acceleration of B is caused by the force exerted by A. The acceleration produced in B is directly proportional to the force exerted on it and inversely proportional to the mass of its own (B’s) mass.

 

Therefore, Force exerted by A on B is equal to the mass of B x acceleration of B

WizIQ Learning Resources

Online Classes

Forces in Equilibrium (Grade 12) by Premaratne Wickramarachchi

Tutorials

Vector Notes by Devendra Chaudhary
The Sixth Problem: Synchronized Motion by Jamahl Peavey
Chapter 9 NCERT 9th Std by Kuldip
Synchronization Two Simple Oscillators by Jamahl Peavey
Synchronization Many Simple Oscillators by Jamahl Peavey

Government Has Decided to Introduce Two IIITs In The Northeast

The Central government is planning to set up two new Indian Institutes of Information Technology in the northeastern region. While addressing the All India Editors conference, Ms. Purandeswari, Minister of State for Human Resource Development said, "The locations are being worked out." The minister informed that 44 new colleges and six engineering colleges will be launched in northeastern states. Ms. Purandeswari said, "Out of the 10 new National Institutes of Technology (NIT) proposed to be opened in the country during the 11th Five Year Plan, 6 NITs are proposed to be opened in Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland and Sikkim."

UP Government Soon to Set Up 12 New Polytechnics

The UP government has decided to open 12 new polytechnics in Uttar Pradesh. One of the senior officials said, "There is a plan to open polytechnics at 12 places, including Jaidpur (Barabanki), Bahedi (Bareilly), Binawar (Badaun), Nanpara (Bahraich) besides other places". The proposal has been sent to district magistrates and hopefully, the classes will begin in the new institutions from the next academic session.

IIT's Blunder Has Messed Up Career of 52 Students

The mistake committed by the IIT has almost ruined the career of 52 undergraduate students.  IIT had promised to 52 students that they would certainly get seats there. However, on 8th July, students came to know that their allotment had not been accepted. Students also have missed a chance to get seats in other engineering colleges offering architecture and pharmaceutical sciences program through AIEEE.  IITs have suggested students to attend a second round of counseling. However, students have been guaranteed a seat even after the second round of counseling.

IGNOU Has Set up New Professional Courses in Collaboration with NIIT

IGNOU has introduced new professional programs like An Executive MBA, eight new finishing school courses and a B.Sc. IT course. These courses have been designed in tandem with the dynamic business needs and for job-hunting purposes. IGNOU Vice Chancellor Mr. V.N. Rajasekharan Pillai and NIIT Chairman Rajendra S. Pawar have signed the partnership agreement on July 10, 2010. These programs will be launched in partnership with NIIT. Mr. V.N. Rajasekharan Pillai, IGNOU Vice Chancellor said, "These courses will go a way ahead in realizing our aim of inclusive education. This is the decade of innovation and we have to train more than 500 million youth in India in this time.” NIIT Chairman, Mr. Pawar said, "These courses are for students from all walks of life. Not all may score high in exams; these courses give an opportunity to them as well.”

Mechanical Engineering Gains Popularity Among Engineering Aspirants

The Central Admission Committee has declared that more & more engineering aspirants are opting for mechanical engineering over other engineering streams. The reason behind the increasing popularity of mechanical engineering as a career option is its impeccable placement record in the last two years. In 2009, companies selected 70 students of mechanical engineering stream from LD Engineering Institute followed by Electrical and Electronics & Communications engineering streams. This year also 51 mechanical engineers have been placed in reputed companies and 21 each from EC and Electrical. Prof KB Bhoyania, Placement officer at LD Engineering College, said, “It has been the trend since the last two years that the highest placement goes to students having taken up mechanical engineering."

Project Ideas, Science Fair Ideas, Exhibition Ideas

The science Fair/ Exhibition time is nearing.

Download the NCERT Guidelines for exhibits HERE

The main objectives of the exhibitions are :

• to provide a forum for children to pursue their natural curiosity and inventiveness to quench their thirst for creativity;
• to make children feel that science is all around us and we can gain knowledge as well as solve  any problems also by relating the learning process to the physical and social environment;
• to lay emphasis on the development of science and technology as a major instrument fo r achieving goals of self-reliance and socioeconomic and socio-ecological development;
• to highlight the role of science and technology for producing good quality and environmental friendly materials for the use of society;
• to encourage children to visualize future of the nation and help them become sensitive and responsible citizens ;
• to analyze how science and technology have developed and is affected by many diverse
  individuals, cultures and societies ;
• to develop critical thinking about global issues to maintain healthy and sustainable societies in
  today's environment;
• to apply mathematics to visualize and solve problems pertaining to everyday life etc.
• to appreciate the role of science and techno logy in meeting the challenges of life such as climate
  change, opening new avenues in the area of agriculture, fertiliser, food processing, biotechnology, green energy, information and communication technology, astronomy, transport,
  games and sports etc.;

 

The Main Theme of this year is

SCIENCE AND TECHNOLOGY FOR CHALLENGES IN LIFE

Jump-Starting NAEP Scores With Financial Rewards

A new study showing that 12th graders paid for correct answers on the National Assessment of Educational Progress scored higher than their peers who weren't given a financial incentive has sparked debate over the question of...financial incentives.

Our Education Week colleague Debra Viadero points out that students don't have much incentive to score higher on their NAEP assessments, as scores don't show up on report cards or count for graduation requirements.

The Core Knowledge Blog has an interesting take on the study in light of the NAEP scores flatline:

The study purports to show "credible evidence" that NAEP underestimates the reading abilities of students enrolled in 12th grade. "Responsible officials should take this into account as they plan changes to the NAEP reading framework and expand the scope of the 12th-grade assessment survey," the authors [of the study] conclude.

In other words, things aren't as bad as they seem? To my mind the salient point about 12th grade NAEP is that it has read like a dead man's EKG for 40 years. Unless you're ready to suggest that high school seniors were more motivated to do well in years gone by (and show evidence) then NAEP has consistently underestimated reading abilities that entire time. Under the same testing conditions (no pay) over several decades, there has been zero change in outcome.

Should stagnant NAEP scores be shaken up—if it's even possible—by giving students monetary incentives?

Physics Online project submission Experiment

Students of Kendriya Vidyalaya Pattom created their first Online Physics Project blog at http://kvphysics.blogspot.com

The teachers found this an effective way of submission and evaluation of data collection projects, which help the students getting trained in effect online content writing and blogging as well as the subject topic of interest.

The students submitted their projects on

• String Theory and GUT


• Superconductivity


• Big Bang Theory


• LHC


• Special Theory of Relativity and


• General Theory of relativity

The students who didn't have easy access to Computers and Internet at home were given the option to submit the project in a file or CD.

Based on the success of this venture more such innovations are expected.

Admission Alerts

 

Jagadguru Rambhadracharya Handicapped University (JRHU) Chitrakoot Uttar Pradesh

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Tamilnadu Common Admissions for Engineerning PG Programmes - TANCA
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JSS College of Pharmacy Mysore Karnataka
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IGNOU B.Arch. Admissions 2010
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