Question

A long straight current carrying wire passes normally through the centre of circular loop. If the current through the wire increases, will there be an induced emf in the loop? Justify.

Answer 1

No, there will be no induced emf in the loop as there is no change in the magnetic flux linked with the circular loop because magnetic field lines are parallel to the plane of the loop. 
ϕ=B.A
​As the angle between the field line and the area vector is 90 degrees, we have zero flux linked with the loop. 
ϕ=BAcosθ
ϕ=BAcos90°ϕ=0