Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions

Two babies are born in a moving train, one in the compartment adjacent to the engine and other in the compartment adjacent to the guard. According to the train frame, the babies are born at the same instant of time. Who is elder according to the ground frame?

An electric bulb, connected to a make and break power supply, switches off and on every second in its rest frame. What is the frequency of its switching off and on as seen from a spaceship travelling at a speed 0.8c?

At what speed the volume of an object shrinks to half its rest value?

Obtain the expression for the current flowing through a conductor having number density of the electron n, area of cross-section A in terms of the drift velocity v_d . 

Derive an expression for the electric potential at any point along the axial line of an electric dipole.

Suppose the initial charge on the capacitor is 6 mC. What is the total energy stored in the circuit initially? What is the total energy at later time?

Which of the following is correct for energy of a dipole in a uniform electric field?

Average power supplied to a capacitor over one complete cycle is ______.

If circuit containing capacitance only, the current ______.

Photoelectric effect is ______.

In n-type semiconductor, the fifth electron ______.

In n-type semiconductor majority carriers and minority carriers are respectively ______.

In p-type semiconductor, the dopant is ______.

In p-type semiconductor, ______.

The electron and hole concentration in a semiconductor in thermal equilibrium is given by ______.

The electric potential at a point on the equatorial line of an electric dipole is ______.

A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at a distance of 2 cm from the centre of the sphere is ______.

A.C. power is transmitted from a power house at a high voltage as ______.

When an ac voltage of 220 V is applied to the capacitor C, then ______.