Electromagnetic Induction · Question 35

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