Electromagnetic Induction Quiz-1

When the current in a coil changes from +2A to –2A in 0.05 second, an emf of 8V is induced in a coil. The coefficient of self-induction of the coil is:

A conducting circular loop is placed in a uniform magnetic field B = 0.25 T, with its plane perpendicular to the field. The radius of the loop is made to shrink at a constant rate of 1 mm/s. The induced emf, when the radius is 2 cm, would be

A conducting ring, of radius r, is placed in a varying magnetic field perpendicular to the plane of the ring. If the rate at which the magnetic field, varies, is x, the (average) electric field intensity, at any point of the ring, would be

The current, through a coil of self inductance. L = 2mH, is given by $I = t ^2 \, e ^{-t}$ at time t. The time taken, to make the induced emf zero, will be

An LC circuit contains a 20 mH inductor, and a 50 $\mu F$ capacitor with an initial charge of 10 mc. The resistance of the circuit is negligible. Let the instant at which the circuit which is closed, be t = 0. At which time the energy stored is completely magnetic?

A rectangular coil, of 300 turns, has an average area of 25 cm$\times$10 cm. The coil rotates, with a speed of 50 cycles per second, in a uniform magnetic field of $4 \times 10 ^{-2} T$, about an axis perpendicular to the field. The peak value of induced emf (in volt), is

Two identical coaxial coils, P and Q, carrying equal amount of current, in the same direction, are brought nearer. The current in

A 50 turns circular coil has as average a radius of 3 cm. It is kept in a magnetic field acting normal to the area of the coil. The magnetic field B is increased from (0.10 T) to (0.35 T) in 2 ms. The average induced emf in the coil, would be

The magnetic flux, through a circular coil of resistance R, changes by an amount $\Delta \phi$ in a time $\Delta t$ . Then the total quantity of electric charge ‘Q’, that passes any point in the coil, during the time $\Delta t$, is represented by

A conducting coil of 600 turns has a self-inductance of 108 mH. The self-inductance of a second identical coil, having of 500 turns, will be