A straight wire of length 0.5 m and carrying a current of 1.2 A is placed in uniform magnetic field of induction 2 T. The magnetic field is perpendicular to the length of the wire. The force on the wire is
2. 4 N
1.2 N
3.0 N
2.0 N
The magnetic field at a distance r from a long wire carrying current I is 0.4 T. The magnetic field at a distance 2r is
0.2 T
0.8 T
0.1 T
1.6 T
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
20 V
40 V
10 V
80 V
The magnetic induction at a point P which is at the distance of 4 cm from a long current carrying wire is 10-3 T. The field of induction at a distance 12 cm from the current will be
3.33 × 10-4 T
1.11 × 10-4 T
3 × 10-3 T
9 × 10-3 T
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 horizontal straight wire, 10m long, extending along the east and west direction, is falling at right angles to the horizontal component of the earth's magnetic field, 0.30 x 10-4 Wbm-2. If the induced emf is 1.5 x 10-3, the velocity of the wire is
5 x10-4 ms-1
5 x 102 ms-1
50 ms-1
5 ms-1
Energy in a current carrying coil is stored in the form of
electric field
magnetic field
dielectric strength
heat
A charged particle of charge q and mass m enters perpendicularly in a magnetic field Kinetic energy of the particle is E, then frequency of rotation
qB/m π
qB/2 πm
qBE/2 πm
qB/2 πE
A current of 3 A flowing in the primary coil is reduced to zero in 0.001 s, 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
