Moving Charges and Magnetism — Physics STD 12 Science — Question

 A man is looking at a small object placed at his near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5X before his eyes. The angular magnification achieved is:

1. 5
2. 2.5
3. 1
4. 0.2

A series combination of three capacitors of capacities 1μF, 2 μF  and  8 μF is connected to a battery of e.m.f. 13 volt. The potential difference across the plates of 2 μF  capacitor will be

(a) 1 V

(b) 8V

(c) 4V

(d)

The critical angle between an equilateral prism and air is 45°. If the incident ray is perpendicular to the refracting surface, then

(a) After deviation it will emerge from the second refracting surface

(b) It is totally reflected on the second surface and emerges out perpendicularly from third surface in air

(c) It is totally reflected from the second and third refracting surfaces and finally emerges out from the first surface

(d) It is totally reflected from all the three sides of prism and never emerges out

A dielectric slab is inserted between the plates of a capacitor. The charge on the capacitor is Q and the magnitude of the induced charge on each surface of the dielectric is Q':

In the thunderstorm, the charges accumulate near the upper edges of clouds are:

Doppler's effect in sound in addition to relative velocity between source and observer, also depends while source and observer or both are moving. Doppler effect in light depend only on the relative velocity of source and observer. The reason of this is

(a) Einstein mass - energy relation	(b) Einstein theory of relativity
(c) Photoelectric effect	(d) None of these

Choke coil works on the principle of

(a) Transient current

(b)  Self induction

(c) Mutual induction

(d) Wattless current

What is the atomic mass (u) of sodium?

Which of the following cannot be used in electronic devices?

Nuclear fusion is common to the pair

(a) Thermonuclear reactor, uranium based nuclear reactor

(b) Energy production in sun, uranium based nuclear reactor

(c) Energy production in sun, hydrogen bomb

(d) Disintegration of heavy nuclei, hydrogen bomb