## Tuesday, July 26, 2011

### Magnetism and magnetic Effects of Current Question Bank for Class 12 CBSE

1. State Biot - Savart Law and apply it to determine the magnetic field at a point on the axis of a circular loop carrying current.

2. State Ampere's Circuital law and apply it to find the magnetic field at a point due to (a) A straight conductor carrying current (b) A current carrying solenoid (c) A current carrying toroid

3. Describe the principle construction and working of a cyclotron.

4. Explain the elements of earth's magnetism.

5. Define the terms magnetisation and magnetic intensity.

6. Compare the properties of dia para and ferromagnetic substances.

7. Describe the principle, construction and working of a moving coil galvanometer.

8. Describe the conversion of a galvanometer in to (a)Voltmeter (b) Ammeter

9. Derive an expression for cyclotron frequency

10. What is hysterisis? Draw the hysterisis curve for a magnetic substance and explain the terms retentivity and coercivity. How do these factors help in selecting suitable materials for (a) Permanent magnet (b) Electromagnet

11. Derive an expression for the intensity of magnetic field (a)on the axial position (b) equatorial position

12. Derive an expression for the torque on a current carrying coil placed in a uniform magnetic field

13. Discuss the equivalence of a current carrying solenoid and a bar magnet

14. Discuss the action of a current carrying coil as an equivalent magnetic dipole.

15. How are magnetic lines of force different from electric lines of force?

16. Define magnetic susceptibility

17. Compare teh properties of an electromagnet and a permanent magnet

18. Explain the domain theory of magnetism

19. Derive an expression for the potential energy of a magnetic dipole in a uniform magnetic field. What is Bohr magneton? Derive an expression for it and calculate its value.

20. Define the terms magnetic meridian and geographic meridian.

21. What is a radial magnetic field? Draw diagram to illustrate how is it realised in a moving coil galvanometer. What is the advantage of a radial magnetic field in MCG?

22. Derive an expression for the force between two straight parallel current carrying conductors of infinite length and hence define one ampere.

23. Derive an expression for the force on a current carrying conductor in a uniform magnetic field.

24. Describe the motion of a charged particle that enters into a magnetic field at right angle. Obtain expression for (i) time period (ii) frequency and (iii) angualr frequency

. Describe the motion of the charged particle when it enters into the field at a certain angle Î¸

25. Find an expression for the force on a moving charge in a magnetci field. State Fleming's left hand rule. Find the force on a moving charge when (i) moving parallel or anti parallel to the field (ii) moving at right angle to the field and (iii) at rest. Also give the definition of unit magnetic field.

26. Compare Biot Savarts law and Ampere's circuital law

27. What is Lorentz force? Give some important characteristics of this force. How can it be used to differentiate the motion of a charged particle in a magnetic field and electric field.

28. Show that the kinetic energy of a charged particle moving in a uniform magnetic field remains constant.

29. Derive an expression for the maximum kinetic energy acquired by a charged particle accelerate din a cyclotron.

30. Why electrons and neutrons cannot be accelerated in a cyclotron?

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