A square coil `ACDE` with its plane vertically is released from rest in a horizontal uniform magnetic field `vec(B)` of length `2L` . The accelaration of the coilis

Options

A. (a) less than `g` for all the time till the loop crosses the magnetic field completely
B. (b) less than `g` when it enters the field and greater than `g` when it comes out of the field
C. (c ) `g` all the time
D. (d) less than `g` when it enters the comes out of the field but equal to `g` when it is within th efield

Answer

D

Explanation

(d) When the coil is within the field, there is no change in the magnetic flux passing through it. Thus, no current will be induced and the acceleration will be `g`. But according to Lenz's law, the induced current will oppose its motin when it enters or leaves the field. Therefore, acceleration will be less than `g`.