Answer
a. clockwise.
b. zero.
c. counterclockwise.
Work Step by Step
By Lenz’s Law, the field caused by the induced current is directed to oppose the change in flux.
a. With switch S open, the magnetic field of the outer loop is zero, where the inner coil is located. As the switch is closed, the magnetic field is out of the page, and increases rapidly. The field of the current induced in the small ring is into the page, to fight the increase in the flux. By the right hand rule, the current in the small ring flows clockwise.
b. With switch S closed for a while, there is no change in flux, and no current.
c. With switch S closed, the magnetic field of the outer loop is out of the page, where the small ring is located. As the switch is opened, the magnetic field is out of the page, and decreases rapidly. The field of the current induced in the small ring is out of the page, to reinforce the failing field, thus fighting the decrease in the flux. By the right hand rule, the current in the small ring flows counterclockwise.
