Electromagnetic induction

A coil having an area 2m2 is placed in a magnetic field which changes from 1Wb/m2 to 4Wb/m2 in an interval of 2 seconds. The e.m.f. induced in the coil will be

• 1 V

• 2 V

• 3 V

• 4 V

The direction of induced e.m.f. during electromagnetic induction is given by

• Faraday's law

• Gauss law

• Ampere circuital law

• Lenz's law

The magnetic flux linked with a coil is given by an equation φ in weber) = 8t2+3t+5. The magnitude of the induced e.m.f. in the coil at the fourth second will be

• 145 V

• 67 V

• 49 V

• 16 V

A metallic ring is attached to the wall of a room. When the north pole of a magnet is brought near to it, the induced current in the ring, as seen from above, will be

• clockwise

• anticlockwise

• first clockwise and then anticlockwise

• first anticlockwise and then clockwise

A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then

• a current will be induced in the coil

• an emf will be induced in the coil

• no current will be induced in the coil

• both emf and current will be induced in the coil

Lenz's law is a consequence of law of

• conservation of linear momentum

• electrical inertia

• conservation of charges

• conservation of energy

In electromagnetic induction, the induced e.m.f. in a coil is independent of

• the change in flux

• the time during which the change in flux takes place

• resistance of the coil

• number of turns of the coil

A conducting circular loop is placed in a uniform magnetic field of 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop (in micro volt) when the radius is 2 cm is

• 4.8 pi

• 3.2 pi

• 1.6 pi

• 0.8 pi

Two different wire loops are concentric and lie in the same plane. The current in the outer loop is clockwise and increases with time. The induced current in the inner loop

• has a direction that depends on the ratio of the radii of the loop

• is clockwise

• is counterclockwise

• is zero

A current-carrying infinitely long wire is kept along the diameter of a circular wire loop, without touching it. Which of the following statement(s) is(are) correct in the given scenario?

I. The emf induced in the loop is zero if the current is constant.

II. The emf induced in the loop is finite if the current is constant.

III. The emf induced in the loop is zero if the current decreases at a steady rate.

• only I

• only III

• I and II

• I and III