Class XII Physics Electromagnetic Induction 1 for JEE & BITSAT Exams

Question 1

This question contains Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
STATEMENT – 1: For a mass M kept at the centre of a cube of side a, the flux of gravitational field passing through its sides is 4 πGM.
STATEMENT – 2: If the direction of a field due to a point source is radial and its dependence on the distance r from the source is given as r^-2, its flux through a closed surface depends only on the strength of the source enclosed by the surface and not on the size or shape of the surface.

Question 2

In a uniform magnetic field of induction B a wire in the form of semicircle of radius r rotates about the diameter of the circle with angular frequency ω. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is R the mean power generated per period of rotation is

Question 3

Some magnetic flux is changed from a coil of resistance 10 ohm. As a result an induced current is developed in it, which varies with time as shown in figure. The magnitude of change in flux through the coil in Webers is-

Question 4

Consider the situation shown in figure. If the switch is closed and after some time it is opened again, the closed loop will show-

Question 5

Consider the situation shown in figure. The wire AB is slid on the fixed rails with constant velocity v. If the wire AB is replaced by a semicircular wire, the magnitude of the induced current will-

Question 6

A circular coil of 100 turns and effective diameter 20 cm carries a current of 1A. It is to turned in a magnetic field B = 3T from a position in which

equal zero. So one in which θ equal 180 °. The work required in this process is

Question 7

A circular coil of 100 turns and effective diameter 20 cm carries a current of 1A. It is to turned in a magnetic field B = 3T from a position in which

equal zero to one in which

equal 180°. The work required in this process is

Question 8

A coil having n turns and resistance R Ω is connected with a galvanometer of resistance 4RΩ. This combination is moved in time t seconds from a magnetic flux W₁ weber to W₂ weber. The induced current in the circuit is