In which of the following devices,the eddy current effect is not used?

$A$ coil is suspended in a uniform magnetic field,with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil,it starts oscillating; it is very difficult to stop. However,if an aluminium plate is placed near the coil,it stops. This is due to:

Eddy currents are used in

The working of magnetic braking of trains is based on

What is an eddy current? Discuss the practical applications of eddy currents. What should be done to decrease the effects of eddy currents?

$A$ metal sheet is placed in a magnetic field that changes from zero to maximum. If the figure shows the direction of eddy currents,then the direction of the magnetic field is: