The dynamo core is laminated because:

Eddy currents are used in

When a bar magnet falls through a long hollow metal cylinder fixed with its axis vertical,the final acceleration of the magnet is

$A$ metallic ring connected to a rod oscillates freely like a pendulum. If a magnetic field is applied in the horizontal direction such that the pendulum swings through the field,the pendulum will:

$A$ light disc made of aluminium (a nonmagnetic material) is kept horizontally and is free to rotate about its axis as shown in the figure. $A$ strong magnet is held vertically at a point above the disc away from its axis. On revolving the magnet about the axis of the disc,the disc will (figure is schematic and not drawn to scale)-

$A$ metal detector works on the principle of: