Moving Charges and Magnetism — Physics STD 12 Science — Question

When a body is weighed on an ordinary balance we demand that the arm should be horizontal if the weights on the two pans are equal. Suppose equal weights are put on the two pans, the arm is kept at an angle with the horizontal and released. Is the torque of the two weights about the middle point (point of support) zero? Is the total torque zero? If so, why does the arm rotate and finally become horizontal?

The dielectric constant decreases if the temperature is increased. Explain this in terms of polarization of the material.

How is displacement current produced between the plates of a parallel plate capacitor during charging?

Define electric dipole moment. Write its S.I. unit.

Why should electrostatic field be zero inside a conductor?

How does an increase in doping concentration affect the width of depletion layer of a p-n junction diode?

In a transistor, doping level in base is increased slightly. How will it affect (i) collector current and (ii) base current?

When a particle moves with constant velocity, its average velocity, its instantaneous velocity and its speed are all equal. Comment on this statement.

What is meant by dielectric? Which is the dielectric among silicon, mica and carbon?