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

Two inductor coils of self-inductance L₁ = 10 H and L₂ = 20 H are placed as shown in the figure. The mutual inductance of the coil is 3H. The equivalent inductance between AB of the system of coils is

1. 36 H

2. 24 H

3. $\frac{20}{3}H$

4. $\frac{38}{3}H$

There is a solenoid of length 1.5 m having 1000 turns per metre, kept in a region where the magnetic field is increased with time as 0.2 T s^-1. (radius of the solenoid is $\frac{10}{\sqrt{\mathrm{\pi }}}\mathrm{cm}$). The current through resistance 10$\Omega$ is

1. 30 A

2. 3 A

3. 0.3 A

4. 0.03 A

A one-metre long metallic rod is rotated with an angular frequency of 400 radians/sec about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant uniform magnetic field of 0.5 tesla parallel to the axis exists everywhere. The emf developed between the centre and the ring is

1. 200 V

2. 100 V

3. 50 V

4. 1000 V

Self-inductances of primary and secondary of an ideal transformer are 90 mH and 40 mH. If the current in the primary decreases at the rate 10³ As^-1, then emf across the secondary is

1. 40 V

2. 90 V

3. 60 V

4. 20 V

A short magnet is allowed to fall along the axis of a horizontal metallic ring. Starting from rest, the distance fallen by the magnet in one second may be:

1. 4 m

2. 5 m

3. 6 m

4. 7 m

In the figure as shown, straight wire carries a constant current. The direction of induced current in the rotating loop about an axis xx' at the instant shown

1. is anticlockwise.

2. is clockwise.

3. there is no current in the loop.

4. maybe clockwise or anticlockwise.