Ten questions. The result tells you which lessons you may skip.
Eddy currents flow in a copper plate when
A strong magnet dropped down a vertical copper tube falls slowly because
The iron core of a transformer is built from thin insulated sheets in order to
A coil of \(50\) turns, each of area \(0.1\,\text{m}^2\), turns at \(100\,\text{rad/s}\) in a field of \(0.2\,\text{T}\). Its peak emf is
The current in a coil is decreasing. The back emf in the coil
A long solenoid is rewound with twice as many turns on the same length. Its self-inductance becomes
An inductor of \(0.5\,\text{H}\) carries \(2\,\text{A}\). The energy stored in it is
Two coils have a mutual inductance of \(0.5\,\text{H}\). The current in one falls from \(2\,\text{A}\) to zero in \(0.01\,\text{s}\). The average emf in the other is
A coil of \(0.3\,\text{H}\) and \(6\,\Omega\) is joined to a \(12\,\text{V}\) cell. The time constant of the circuit is
A switch opens in a circuit that contains an inductor. At that instant the quantity that cannot change suddenly is