Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

What is the net force on the square coil

The value of photoelectric current depends :

An electron microscope is superior to an optical microscope in(a) Having better resolving power  (b) Being easy to handle  (c) Low cost  (d) Quickness of observation 

A 100% efficient transformer has 100 turns in the primary and 25 turns in its secondary coil. If the current in the secondary coil is 4 amp, then the current in the primary coil is(a) 1 amp (b) 4 amp(c) 8 amp (d) 16 amp

Consider the motion of the tip of the minute hand of a clock. In one hour:

1. The displacement is zero.
2. The distance covered is zero.
3. The average speed is zero.
4. The average velocity is zero.

The ratio of intensity of magnetisation and magnetising field is called:

A positively charged particle moving along x-axis with a certain velocity enters a uniform electric field directed along positive y-axis. Its(a) Vertical velocity changes but horizontal velocity remains constant(b) Horizontal velocity changes but vertical velocity remains constant(c) Both vertical and horizontal velocities change(d) Neither vertical nor horizontal velocity changes

Which of the following is wrong statement(a) An emf can be induced between the ends of a straight conductor by moving it through a uniform magnetic field(b) The self induced emf produced by changing current in a coil always tends to decrease the current(c) Inserting an iron core in a coil increases its coefficient of self induction(d) According to Lenz's law, the direction of the induced current is such that it opposes the flux change that causes it

Polarisation of light was first successfully explained by: