The magnetic flux linked with a coil is given by the equation : Φ = 5 t2 + 3 t + 6.Find out the induced e.m.f. in 4 seconds ?
20 V
40 V
10 V
80 V
Energy in a current carrying coil is stored in the form of
electric field
magnetic field
dielectric strength
heat
The current changes from +2 A to -2 A in 0.05 s, and emf of 8V is found induced in the coil.Then the coefficient of self-induction of the coil is :
0.2H
0.4H
0.8H
0.1H
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
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 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
Two inductors each of inductance L are connected in parallel. What is their equivalent inductance?
2L
L
L/2
L/4
A magnetic field of 2 x 10-2 T acts at right angles to a coil of area 100 cm2 with 50 turns. The average e.m.f. induced in the coil is 0.1 V when it is removed from the field in t sec. The value of t is
0.1 s
10 s
0.01 s
1s
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 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
