Electromagnetic Induction · Question 33

A circular disc of radius 0.2 meter is placed in a uniform magnetic field of induction 1 ( Wbm2 ) in such a way that its axis makes an angle of 60 with B. The magnetic flux linked with the disc is

1. 0.08 Wb
2. 0.01 Wb
3. 0.02 Wb
4. 0.06 Wb

Two coils of self inductance 2 mH and 8 mH are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is

1. 16 mH
2. 10 mH
3. 6 mH
4. 4 mH

As a result of change in the magnetic flux linked to the closed loop as shown in the figure, an e.m.f. V volt is induced in the loop. The work done (joule) in taking a charge Q coulomb once along the loop is [figure]

1. QV
2. 2QV
3. QV/2
4. zero

A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is

1. 5 seconds
2. 1/5 seconds
3. 40 seconds
4. 20 seconds

The magnetic flux through a circuit of resistance R changes by an amount in a time t. Then the total quantity of electric charge Q that passes any point in the circuit during the time t is represented by

1. Q = 1R t
2. Q = R
3. Q = t
4. Q = R t

For a coil having L = 2 mH, current flow through it is I = t2e-t then, the time at which emf becomes zero

1. 2 sec
2. 1 sec
3. 4 sec
4. 3 sec