If conducting triangle is pulled out with a uniform velocity from the uniform magnetic field, as shown in the figure, then which graph of induced current versus time is possible?
       

1.             2. 
3.             4. 

Two circular coils of different radii lie in the same plane with their centres at same point i.e. inner coil is surrounded by a bigger outer coil. If the current in the outer coil is clockwise and increasing with time, then induced current in the inner loop is

1. Anticlockwise

2. Zero

3. Clockwise

4. Depends on resistances

A field of 0.2 T acts perpendicular to a coil of area 100cm² with 50 turns. If the coil is removed within 0.1s from the field, then the minimum emf induced in the coil is

1. 1 V

2. 2 V

3. 3 V

4. 4 V

If by keeping number of turns per unit length constant, the volume of an air-core inductor is doubled, then its self-inductance will become/remain

1. Two times

2. Half

3. Same

4. Four times

Eddy currents are used in:

1. Induction furnace

2. Electromagnetic brakes

3. Speedometers

4. All of these

A square loop of sides 4 cm having a resistance of 2$\Omega$ is placed normal to a magnetic field. If the magnetic field is gradually reduced at the rate of 0.02 T/s. The induced current in the loop is

1. 8 $\mu A$

2. 2 $\mu A$

3. 16 $\mu A$

4. 6 $\mu A$

The direction of the runway on the airport should be

1. Along N-A

2. Along E-W

3. Along NW-SE

4. Along NE-SW

A metallic wheel (of radius l and 8 spokes) is rotated in a uniform magnetic field B as shown. The motional EMF across centre and rim is given by

1. $4B{l}^2\omega$

2. $2B{l}^2\omega$

3. $8B{l}^2\omega$

4. $\frac{1}{2}B{l}^2\omega$

Charged pollen grains are lying on a frictionless table. These are now subject to a certain field and are found to be moving by these fields. The field cannot be

1. Time-dependent electric field

2. Position dependent electric field

3. Time-dependent magnetic field

4. Position dependent magnetic field

The magnetic field in the region is decreasing in such a way that dB/dt = $\gamma$. If resistance per unit length of the loop shown is $\lambda$, then, the current flowing in the loop is given by

1. $\frac{2\pi r\gamma }{\lambda }$ Clockwise

2. $\frac{2\pi r\gamma }{\lambda }$ Anticlockwise

3. $\frac{r\gamma }{2\lambda }$ Clockwise

4. $\frac{r\gamma }{2\lambda }$ Anticlockwise