Predict the direction of induced current in the situations described by the following figures.

(N/A) The direction of the induced current in a closed loop is given by Lenz's law,which states that the polarity of induced emf is such that it tends to produce a current which opposes the change in magnetic flux that produced it.
$(a)$ As the North pole of the magnet moves towards the coil,the magnetic flux through the coil increases. To oppose this,the coil develops a North pole on the face towards the magnet. Thus,the induced current flows along $qrpq$.
$(b)$ As the North pole of the magnet moves away from the coil,the magnetic flux decreases. To oppose this,the coil develops a South pole on the face towards the magnet. Thus,the induced current flows along $prqp$ in the left coil and $zyxz$ in the right coil.
$(c)$ When the tapping key is just closed,the current in the left loop increases,creating an increasing magnetic field. By Lenz's law,the right loop develops an induced current to oppose this increase. The direction is along $zyxz$.
$(d)$ When the rheostat setting is changed to increase the resistance,the current in the right loop decreases,leading to a decrease in magnetic flux. The left loop develops an induced current to oppose this decrease. The direction is along $yzxy$.
$(e)$ When the tapping key is just released,the current in the primary coil drops to zero,causing a rapid decrease in magnetic flux. The secondary coil develops an induced current to oppose this change. The direction is along $xryx$.
$(f)$ No current is induced because the magnetic field lines are parallel to the plane of the loop,resulting in zero magnetic flux through the loop at all times.