The cores used in transformers are laminated to

Eddy currents are used in

$A$ sheet is placed on a horizontal surface in front of a strong magnetic pole. $A$ force is needed to:
$A$. hold the sheet there if it is magnetic.
$B$. hold the sheet there if it is non-magnetic.
$C$. move the sheet away from the pole with uniform velocity if it is conducting.
$D$. move the sheet away from the pole with uniform velocity if it is both,non-conducting and non-polar.
Choose the correct statement$(s)$ from the options given below:

$A$ 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:

When a small magnet is allowed to fall through an aluminium pipe,it falls with an acceleration less than $g$. Why?

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