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 incrreasing, hence anticlockwise emf
In position III, flux is decreasing, hence clockwise emf