The adjoining figure shows two bulbs \(B_1\) and \(B_2\) resistor \(R\) and an inductor \(L\). When the switch \(S\) is turned off 

1.	Both \(B_1\) and \(B_2\) die out promptly.
2.	Both \(B_1\) and \(B_2\) die out with some delay.
3.	\(B_1\) dies out promptly but \(B_2\) with some delay.
4.	\(B_2\) dies out promptly but \(B_1\) with some delay.

An inductance L and a resistance R are first connected to a battery. After some time the battery is disconnected but L and R remain connected in a closed circuit. Then the current reduces to 37% of its initial value in time ?

1. RL sec

2. $\frac{R}{L}sec$

3. $\frac{L}{R}sec$

4. $\frac{1}{LR}sec$

An e.m.f. of 15 volt is applied in a circuit containing 5 henry inductance and 10 ohm resistance. The ratio of the currents at time t = ∞ and at t = 1 second is 

1. $\frac{e^{1/2}}{e^{1/2}-1}$

2. $\frac{e^2}{e^2-1}$

3. 1 – e^–1

4. e^–1

Two conducting circular loops of radii \(R_1\) and \(R_2\) are placed in the same plane with their centres coinciding. If \(R_1>>R_2\), the mutual inductance \(M\) between them will be directly proportional to:

A circular loop of radius R carrying current I lies in the x-y plane with its centre at the origin. The total magnetic flux through the x-y plane is 

1. Directly proportional to I

2. Directly proportional to R

3. Directly proportional to R²

4. Zero

Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be 

1. Maximum in situation (A)

2. Maximum in situation (B)

3. Maximum in situation (C)

4. The same in all situations

A conductor ABOCD moves along its bisector with a velocity of 1 m/s through a perpendicular magnetic field of 1 wb/m², as shown in fig. If all the four sides are of 1m length each, then the induced emf between points A and D is

1. 0

2. 1.41 volt

3. 0.71 volt

4. None of the above

A wire cd of length l and mass m is sliding without friction on conducting rails ax and by as shown. The vertical rails are connected to each other with a resistance R between a and b. A uniform magnetic field B is applied perpendicular to the plane abcd such that cd moves with a constant velocity of

1. $\frac{mgR}{Bl}$

2. $\frac{mgR}{B^2{l}^2}$

3. $\frac{mgR}{B^3{l}^3}$

4. $\frac{mgR}{B^{2}l}$

The figure shows three circuits with identical batteries, inductors, and resistors. Rank the circuits according to the current, in descending order, through the battery \((i)\) just after the switch is closed and \((ii)\) a long time later:

The variation of induced emf (E) with time (t) in a coil if a short bar magnet is moved along its axis with a constant velocity is best represented as:

1.		2.
3.		4.