Atoms — Physics STD 12 Science — Question

Which of one is correct

(a)

(b)

(c)

(d)

For a common base configuration of PNP transistor   then maximum current gain in common emitter configuration will be

(a) 12

(b) 24

(c) 6

(d) 5

In the following transitions, which one has higher frequency

(a) 3 – 2

(b) 4 – 3

(c) 4 – 2

(d) 3 – 1

Out of gravitational, electromagnetic, Vander Waals, electrostatic and nuclear forces; which two are able to provide an attractive force between two neutrons

(a) Electrostatic and gravitational

(b) Electrostatic and nuclear

(c) Gravitational and nuclear

(d) Some other forces like Vander Waals

In interchanging the corresponding positions of battery and galvanometer in a Wheatstone bridge, the balanced position:

In Thomson experiment of finding e/m for electrons, beam of electron is replaced by that of muons (particle with same charge as of electrons but mass 208 times that of electrons). No deflection condition in this case satisfied if

(a) B is increased 208 times	(b) E is increased 208 times
(c) B is increased 14.4 times	(d) None of these

To convert mechanical energy into electrical energy, one can use:

1. DC dynamo.
2. AC dynamo.
3. Motor.
4. Transformer.

The magnet of a vibration magnetometer is heated so as to reduce its magnetic moment by 19%. By doing this the periodic time of the magnetometer will

(a) Increase by 19%

(b) Decrease by 19%

(c) Increase by 11%

(d) Decrease by 21%

What is the maximum energy that can be stored in a capacitor?