Same as problem 4 except the coil A is made to rotate about a vertical axis (figure). No current flows in B if A is at rest. The current in coil A, when the current in B (at t = 0) is counter-clockwise and the coil A is as shown at this instant, t = 0, is

(a) Constant current clockwise

(b) Varying current clockwise

(c) Varying current counter clockwise

(d) Constant current counter clockwise

An aeroplane, with its wings spread 10m, is flying at a speed of 180 km/h in a horizontal direction. The total intensity of earth’s field at that part is 2.5 × 10^-4Wb/m² and the angle of dip is 60°. The emf induced between the tips of the plane wings will be…………..

Two conducting circular loops of radii R₁ and R₂ are placed in the same plane with their centres coinciding. If R₁ » R₂, the mutual inductance M between them will be directly proportional to:

A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil?

Three positions shown describe:

(a) the magnet's entry

(b) magnet is completely inside and

(c) magnet's exit

Figure shows a circuit that contains four identical resistors with resistance R = $2.0\Omega ,$  two identical inductors with inductance L = 2.0mH and an ideal battery with emf E = 9V. The current ‘i’ just after switch ‘S’ is closed will be:

An inductor coil stores 64J of magnetic field energy nad dissipates energy at the rate of 640W when a current of 8A is passed through it. If this coil is joined across an ideal battery, find the time constant of the circuit in seconds: