Electromagnetic...

A small circular coil of radius 1 cm and number of turns 100 is placed inside a long solenoid of radius 5 cm and number of turns 8 per cm. The axis of the coil is parallel to the solenoid axis. Then, the coefficient of mutual inductance of the two coils is (in milli Henry)

An athlete is running at a speed of 30 kmh$$^{-1}$$ towards east, holding a 3 m metallic rod horizontally. The horizontal component of the earth, magnetic field in this region is $$3 \times 10^{-4} $$ Tesla and the angle of dip is 30$$^o$$. Then, the emf induced across the ends of the rod is

An ac generator consists of a coil of 200 turns, 100 cm in diameter. If the coil rotates at 500 rpm in a magnetic field of 0.25T, then the maximum induced emf

In an a.c. generator the speed at which the coil rotates is doubled. How would this affect the frequency of output voltage ?

Complete the following sentence:

A car moves up a plane road. The induced emf in the axle connecting the two wheels is maximum when it moves

An airplane with wingspan $$50 m$$ is flying horizontally with a speed of $$360 km hr^{-1}$$ over a place where the vertical component of the earth's magnetic field is $$2 \times 10^{-2}$$. The potential difference between the tips of the wings would be

One conducting U tube can slide inside another as shown in figure, maintaining electric contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant speed v, then the emf induced in the circuit in terms of B, $$l$$ and v where $$l$$ is the width of each tube, will be

What determines the frequency of a.c. produced in a generator?

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