A current of 3A flowing in the primary coil is reduced to zero in 0.001s, the induced e.m.f. in the secondary is 15000 V. The mutual inductance between the two coils is
0.5 H
5 H
1.5 H
10 H
The inductance of a coil is directly proportional to
its length
the number of turns
the resistance of the coil
the square of the number of turns
A magnet is allowed to fall through a metallic ring. During fall, its acceleration is
less than g
equal to g
greater than g
equal to 2g
Two inductors each of inductance L are connected in parallel. What is their equivalent inductance?
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
5π volts
2π volts
π volts
4π volts
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
12.6 V
0.126 V
1.26 V
0.013 V
A current carrying solenoid contains an iron rod inside it. A current flows in the solenoid due to a DC source, of constant emf, connected across the ends of the solenoid. When the rod is pulled out of the solenoid, then the current in the solenoid will
Increase
Decrease
Remain constant
Becomes zero
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 coil is wound in a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor of 3 and the number of turns per unit length remains the same, the self inductance increases by a factor of :
3
9
27
8
A 100 mH coil carries a current of 1 A. Energy stored in the magnetic field is
0.5 J
1 J
0.1 J
0.05 J
