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

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

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

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

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

Calculate the net emf across A and B shown in Figure 1 below :

Obtain an expression for electric potential ‘V’ at a point in an end-on position i.e. axial position of the electric dipole. 

Derive the law of reflection using Huygen’s Wave Theory. 

(i) Draw a labelled circuit diagram of a half wave rectifier and give its output waveform.

(ii) Draw a symbol for NOR gate and write its its truth table. 

(i) Draw a neat circuit diagram to study the input and output characteristics of a common emitter transistor.

(ii) Draw the symbol for AND gate and write its truth table.

With what type of source of light are cylindrical wave fronts associated?

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? 

A metallic wire having a length of 2 m and weight of 4 x 10^-3 N is found to remain at rest in a uniform and transverse magnetic field of 2 x 10^-4 T. Current flowing through the wire is:

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 total energy of an electron in the ground state of the hydrogen atom is -13·6 eV. Its total energy, when a hydrogen atom is in the first excited state, is: 

Write the expression for the Lorentz force F in vector form.

A coil has a self-inductance of 0·05 Henry. Find the magnitude of the emf induced in it when the current flowing through it is changing at the rate of 100 As^-1.