Question

The long straight wire in the figure carries a current I that is decreasing with time at a constant rate. The circular loops A, B, and C all lie in a plane containing the wire. The induced emf in each of the loops A, B, and C is such that

a) no emf is induced in any of the loops. 

b) a counterclockwise emf is induced in all the loops. 

c) loop A has a clockwise emf, loop B has no induced emf, and loop C has a counterclockwise emf. 

d) loop A has a counter-clockwise emf, loop B has no induced emf, and loop C has a clockwise emf. 

e) loop A has a counter-clockwise emf, loops B and C have clockwise emfs. 

Answer 1

Net flux through B is zero so no emf will be introduced in loop B.
Magnetic field lines is coming out of the paper at loop A, so when current I decreases a current will be induced in loop A to maintain magnetic field lines in the same direction. Direction of current will be anticlockwise.

Magnetic field lines are going inside the paper at loop C. So a current will be induced which will maintain magnetic field in the same direction. Direction of current will be clockwise.

Option (d) meets all the criteria.