A field of 0.2 T acts perpendicular to a coil of area 100cm2 with 50 turns. If the coil is removed within 0.1s from the field, then the minimum emf induced in the coil is
1. 1 V
2. 2 V
3. 3 V
4. 4 V
If by keeping number of turns per unit length constant, the volume of an air-core inductor is doubled, then its self-inductance will become/remain
1. Two times
2. Half
3. Same
4. Four times
Eddy currents are used in:
1. Induction furnace
2. Electromagnetic brakes
3. Speedometers
4. All of these
A square loop of sides 4 cm having a resistance of 2 is placed normal to a magnetic field. If the magnetic field is gradually reduced at the rate of 0.02 T/s. The induced current in the loop is
1. 8
2. 2
3. 16
4. 6
The direction of the runway on the airport should be
1. Along N-A
2. Along E-W
3. Along NW-SE
4. Along NE-SW
A metallic wheel (of radius l and 8 spokes) is rotated in a uniform magnetic field B as shown. The motional EMF across centre and rim is given by
1.
2.
3.
4.
Charged pollen grains are lying on a frictionless table. These are now subject to a certain field and are found to be moving by these fields. The field cannot be
1. Time-dependent electric field
2. Position dependent electric field
3. Time-dependent magnetic field
4. Position dependent magnetic field
The magnetic field in the region is decreasing in such a way that dB/dt = . If resistance per unit length of the loop shown is , then, the current flowing in the loop is given by
1. Clockwise
2. Anticlockwise
3. Clockwise
4. Anticlockwise
Two inductor coils of self-inductance L1 = 10 H and L2 = 20 H are placed as shown in the figure. The mutual inductance of the coil is 3H. The equivalent inductance between AB of the system of coils is
1. 36 H
2. 24 H
3.
4.
There is a solenoid of length 1.5 m having 1000 turns per metre, kept in a region where the magnetic field is increased with time as 0.2 T s-1. (radius of the solenoid is ). The current through resistance 10 is
1. 30 A
2. 3 A
3. 0.3 A
4. 0.03 A