Electromagnetic Induction

If a current of 3 A fl.owing in the primary coil is reduced to zero in 0.01 s then the induced emf in the secondary coil is 1500 V, the mutual inductance between the two coils is :

• 0.5 H

• 5 H

• 1.5 H

• 10 H

Two similar coils are kept mutually perpendicular such that their centres coincide. At the centre, find the ratio of the magnetic field due to one coil and the resultant magnetic field through both coils, if the same current is flown :

• 1 : $\sqrt{2}$

• 1 : 2

• 2 : 1

• $\sqrt{3}$ : 1

Lenz's law is based on the principle of conservation of

• mass

• charge

• momentum

• energy

A conducting square loop of side L and resistance R moves in its plane with a uniform velocity v, perpendicular to one of its sides. A magnetic field of induction B, constant in space and time and pointing perpendicularly into the plane of the square, exists  everywhere in space. The current induced in the loop is

• BLv/R in the clockwise direction

• BLv/R in the anticlockwise direction

• 2 BLv/R in the clockwise direction

• zero

Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon

• the rates at which currents are changing in the two coils

• relative position and orientation of the two coils

• the materials of the wires of the coils

• the currents in the two coils

A circular coil has 500 turn of wire and its radius is 5 cm. The self inductance of the coil is

• 25 x 10^-3 mH

• 25 mH

• 50 x 10^-3 H

• 50 x 10^-3 mH

The unit of inductance is

• $\frac{\mathrm{volt}}{\mathrm{ampere}}$

• $\frac{\mathrm{joule}}{\mathrm{ampere}}$

• $\frac{\mathrm{volt}-\mathrm{second}}{\mathrm{ampere}}$

• $\frac{\mathrm{volt}-\mathrm{ampere}}{\mathrm{second}}$

1 Wb/m² is equal to

• 10⁴ G

• 10² G

• 10^-2 G

• 10^-4 G

A steady current of 5 A is maintained for 45 min. During this time it deposits 4.572 g of zinc at the cathode of a voltmeter. ECE of zinc is

• 3.38 × 10^-4 g/C

• 3.397 × 10^-4 g/C

• 3.384 × 10^-3 g/C

• 3.394 × 10^-3 g/C

A magnetising field of 1600 A/m produces a magnetic flux 2.4 x10^-5 Wb in an iron bar of cross-sectional area 0.2 cm². The susceptibility of an iron bar will be

• 1788

• 1192

• 596

• 298