An aircraft has a wing span of 35 m. It is flying horizontally with a speed of 9.ms^-1 and the vertical component of earth's magnetic field is 4 x 10^-5T. The potential difference between the tips of the wings will be

A horizontal straight wire, 10m long, extending along the east and west direction, is falling at right angles to the horizontal component of the earth's magnetic field, 0.30 x 10^-4 Wbm^-2. If the induced emf is 1.5 x 10^-3, the velocity of the wire is 

Two coils have a mutual inductance of 0.005 H. The current changes in the first coil according to the equation I = I₀ sin ωt where I0 = 10A and ω = 100π rad/sec. The maximum value of e.m.f. in the second coil is 

The magnetic energy in an inductor changes from maximum value to minimum value in 5 ms when connected to an a.c. source. The frequency of the source is :

The inductance of a coil is directly proportional to 

Energy in a current carrying coil is stored in the form of 

A rectangular coil of 20 turns and area of cross-section 25 cm² has a resistance of 100 Ω. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of 1000 T per second, the current in the coil is

The number of turns in a secondary coil is twice the number of turns in primary. A Leclanche cell of 1.5 V is connected across the primary. The voltage acrosss secondray is 

The magnetic flux linked with a coil is given by the equation : Φ = 5 t² + 3 t + 6. The induced e.m.f. in the coil in the fourth second will  be

A circuit has a self inductance of 1 H and carries a current of 2 A. To prevent sparking when the circuit is broken, a capacitor which can withstand 400 V is used. The capacitance of the capacitor is