A square loop `ABCD` of edge a moves to the right with a velocity `v` parallel to `AB` . There is a uniform magnetic field of magnitude `B` , direction into the paper, in the region between `PQ` and `RS` only. I, II and III are three ppositions of the loop.
(i) The emf induced in the loop has magnitude `B` a `v` in all three position
(iii) Induced emf is anticlockwise in position II
(iv) The induced emf is clockwise in position III

Options

A. (i), (iii)
B. (ii), (iii), (iv)
C. (i), (ii)
D. (iii),(iv)

Answer

B

Explanation

In position II, change in flux = 0, emf = 0.
In position I, and III, e = Bav
In position I, flux is increasing, hence anti-clockwise emf.
If position III, flux is decreasing, hence clockwise emf.