Answer
a. counterclockwise.
b. clockwise.
c. zero.
Work Step by Step
By Lenz’s Law, the field caused by the induced current is directed to oppose the change in flux.
a. The field is into the page and increasing, and so is the flux. To fight this change, the secondary field of the induced current points out of the page. By the right hand rule, the induced current is counterclockwise.
b. The field is into the page and decreasing, and so is the flux. To fight this change, the secondary field of the induced current points into the page, to reinforce the failing field. By the right hand rule, the induced current is clockwise.
c. The field is constant so there is no change in flux. There is no induced emf, and no induced current.
