Two inductors each of inductance L are connected in parallel. What is their equivalent inductance?
2L
L
L/2
L/4
A coil of 1000 turns of wire is wound on a book and this book is lying on the table. The vertical component of earth's magnetic field is 0.6 x 10-4 T and the area of the coil is 0.05m2. The book is turned through 180o about a horizontal axis in 0.1 second. The average e.m.f. induced in the coil is
0.03 V
0.06 V
zero
0.6 V
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
50 Hz
200 Hz
500 Hz
20 Hz
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 north pole of a long horizontal bar magnet is brought closer to the vertical conducting plane along perpendicular direction. The induced current in the conducting plane is :
anticlockwise
clockwise
horizontal
vertical
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 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
What is the coefficient of mutual induction when the magetic flux changes by 2 x 10-2 Wb and chnge in current is 0.01A?
3 H
0.5 H
2 H
If a current is passed through a spring, then the spring
expands
gets compressed
remains same
None of these
A current varying at the rate of 3A/s in a coil generates an e.m.f. of 8mV in a nearby coil. The mutual inductance of hte two coils is
2.66 H
2.66 x 10-3 mH
0.266 H
2.66 mH
