ISC (Science) ISC Class 12 - CISCE Question Bank Solutions for Physics (Theory)

Name a material which is used in making control rods in a nuclear reactor.

With the help of a suitable example and an equation, explain the term pair production.

A converging lens of focal length 40 cm is kept in contact with a diverging lens of focal length 30 cm. Find the focal length of the combination .

How can the spherical aberration produced by a lens be minimized? 

Two thin lenses having optical powers of -10D and+ 6D are placed in contact with each other. The focal length of the combination is: 

The atomic mass of Uranium `""_92^238"U"` is 238.0508 u, while that of Thorium `""_90^234"Th"` is 234.0436u, and that of Helium `""_2^4"He"` "is 4.0026u. Alpha decay converts `""_92^238"U"` into `""_92^234"Th"` as, shown below:

`""_92^238"U" -> ( ""_90^234"Th" + ""_2^4"He" + "Energy" )`

What is a neutrino?

State how the focal length of a glass lens (Refractive Index 1.5) changes when it is completely immersed in: 

(i) Water (Refractive Index 1.33)
(ii) A liquid (Refractive Index 1.65)

A thin converging lens of focal length 12 cm is kept in contact with a thin diverging lens of focal length 18 cm. Calculate the effective/equivalent focal length of the combination.

What conclusion is drawn from Rutherford’s scattering experiment of α-particles?

If an object is placed at a distance of 10 cm in front of a concave mirror of a focal length of 20 cm, the image formed will be ______.

What is 'Pair production'?

Why does a car driver use a convex mirror as a rear-view mirror?

A lens of focal length f is divided into two equal parts and then these parts are put in a combination as shown in the figure below.

1. What is the focal length of L₁?
2. What is the focal length of the final combination?

A circular coil carrying a current I has radius R and number of turns N. If all the three, i.e. the current
I, radius R and number of turns N are doubled, then, the magnetic field at its centre becomes:

(a) Double

(b) Half

(c) Four times

(d) One fourth

An object is kept on the principal axis of a concave mirror of focal length 10 cm. at a distance of 15
cm from its pole. The image formed by the mirror is:

(a) Virtual and magnified

(b) Virtual and diminished

(c) Real and magnified

(d) Real and diminished

An emf of 2V is induced in a coil when the current in it is changed from 0A to 10A in 0·40 sec. Find the coefficient of self-inductance of the coil.

Explain the term hysteresis

Obtain an expression for magnetic flux density B at the centre of a circular coil of radius R, having N turns and carrying a current I