Motional Electromotive Force (e.m.f.)

A wire 5 m long is supported horizontally at a height of 15 m along an east-west direction. When it is about to hit the ground, calculate the average e.m.f. induced in it. (g = 10 m/s²)

An aeroplane, with its wings spread 10 m, is flying at a speed of 180 km/h in a horizontal direction. The total intensity of earth's field at that part is 2.5 × 10^-4 Wb/m² and the angle of dip is 60°. The emf induced between the tips of the plane wings will be ______.

A rod of mass m and resistance R slides smoothly over two parallel perfectly conducting wires kept sloping at an angle θ with respect to the horizontal (Figure). The circuit is closed through a perfect conductor at the top. There is a constant magnetic field B along the vertical direction. If the rod is initially at rest, find the velocity of the rod as a function of time.

A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. This can be because ______.

1. the magnetic field is constant.
2. the magnetic field is in the same plane as the circular coil and it may or may not vary.
3. the magnetic field has a perpendicular (to the plane of the coil) component whose magnitude is decreasing suitably.
4. there is a constant magnetic field in the perpendicular (to the plane of the coil) direction.

Derive an expression for the total emf induced in a conducting rotating rod.

A simple pendulum with a bob of mass m and conducting wire of length L swings under gravity through an angle θ. The component of the earth's magnetic field in the direction perpendicular to the swing is B. Maximum emf induced across the pendulum is ______.

(g = acceleration due to gravity)

An aircraft of wing span of 50 m flies horizontally in the Earth's magnetic field of 6 x 10^-5 T at a speed of 400 m/s. Calculate the emf generated between the tips of the wings of the aircraft.

Find the current in the sliding rod AB (resistance = R) for the arrangement shown in figure. B is constant and is out of the paper. Parallel wires have no resistance. v is constant. Switch S is closed at time t = 0.