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
If a current is passed through a spring, then the spring
expands
gets compressed
remains same
None of these
A long solenoid has 200 turns/cm and carries a current I. The magnetic field at its centre is 5.28 x 10-2 Wbm-2. Another long solenoid has 100 turns/cm and it carries a current I/3. The value of the magnetic field at its centre is
1.05 x 10-2 Wb m-2
1.05 x 10-5 Wb m-2
1.05 x 10-3 Wb m-2
1.05 x 10-4 Wb m-2
A coil of resistance R and inductance L is connected to a battery of e.m.f. E volts. The final current in the coil is
Two inductors each of inductance L are connected in parallel. What is their equivalent inductance?
2L
L
L/2
L/4
A coil of area 100 cm2 has 500 turns. Magnetic field of 0.1 Wb/m2 is perpendicular to the coil. The field is reduced to zero in 0.1s.Calculate the emf induced in the coil ?
zero
5 V
1 V
50 V
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
1 A
50 A
0.5 A
5 A
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
1.5 V
3 V
240 V
A current of 3 A 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
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
