Electromagnetic Induction — Physics STD 12 Science — Question

In electromagnetic induction, the induced charge in a coil is independent of

(a) Change in the flux	(b) Time
(c) Resistance in the circuit	(d) None of the above

A beam of ions with velocity 2   enters normally into a uniform magnetic field of 4 If the specific charge of the ion is 5 , then the radius of the circular path described will be

(a) 0.10 m

(b) 0.16 m

(c)  0.20 m

(d) 0.25 m

An alternating current of frequency 200 rad/sec and peak value 1A as shown in the figure, is applied to the primary of a transformer. If the coefficient of mutual induction between the primary and the secondary is 1.5 H, the voltage induced in the secondary will be

(a) 300 V

(b) 191 V

(c) 220 V

(d) 471 V

Which of the following quantities is the same for all ideal gases at the same temperature?

1. The kinetic energy of 1 mole.
2. The kinetic energy of 1g.
3. The number of molecules in 1 mole.
4. The number of molecules in 1g.

Choose the correct answer from the alternatives given.
The amplitude of an electromagnetic wave in vaccum is doubled with no other changes made to the wave. As a result of this doubling of the amplitude, which of the following statement is correct?

Water of volume 2 litre in a container is heated with a coil of 1 kW at 27 ^oC. The lid of the container is open and energy dissipates at rate of 160 J/s. In how much time temperature will rise from 27^oC to 77^oC [Given specific heat of water is 4.2 kJ/kg]

(a) 8 min 20 s

(b) 6 min 2 s

(c) 7 min

(d) 14 min

The mass of ions deposited during a given interval of time in the process of electrolysis depends on

(a) The current

(b) The resistance

(c) The temperature

(d) The electric power

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.

For P-type semiconductors, impurity elements are used :

Light of different colours propagates through air

(a) With the velocity of air

(b) With different velocities

(c) With the velocity of sound

(d) Having the equal velocities