Magnetism And Matter — Physics STD 12 Science — Question

The antenna current of an AM transmitter is 8 A when only carrier is sent but increases to 8.96 A when the carrier is sinusoidally modulated. The percentage modulation is (a) 50%   (b) 60%(c) 65%   (d) 71%

The value of the basic unit of the charge is:

The battery connections required to forward bias a pn junction are ____________:

If the frequency of an A.C is made 4 times of its initial value, the inductive reactance will.

An electron and a proton are in motion with equal kinetic energy. Which of the following relation is true ?

A particle is fastened at the end of a string and is whirled in a vertical circle with the other end of the string being fixed. The motion of the particle is:

1. Periodic.
2. Oscillatory.
3. Simple harmonic.
4. Angular simple harmonic.

Assertion     :   If the distance between parallel plates of a capacitor is halved and dielectric constant is made three times, then the capacitor becomes 6 times.
Reason        : Capacity of the capacitor does not depend upon the nature of the material. (a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.