Some important questions for class 12

• A charged particle enters a magnetic field region in a direction perpendicular to the direction of the magnetic field. Will there be any change in the particle’s (i) kinetic energy (ii) momentum

Ans:

In the presence of a magnetic field, the particle experiences a magnetic force in the direction perpendicular to the directions of the moving particle and the magnetic field. The magnitude of
velocity of the particle remains the same while its direction changes. Hence, kinetic energy of the particle will not change while its momentum will change

• Write the undesirable effects and their causes during signal transmissions.

Solution:

There are four undesirable effects during signal transmission. The following table lists these effects with their respective causes.

1. Attenuation   Decrease in signal strength due to energy loss

2. Distortion     Due to wave form perturbation

3. Interference    Due to contamination of extraneous signals

4. Noise      Due to random electrical signals