Lenz force acting on a conducting rod moving in a magnetic field is ____

Options

A. proportional to length.
B. proportional to square of length.
C. inversely proportional to length.
D. inversely proportional to square of length.

Answer

B

Explanation

Lenz force is
`F=BI l=B (epsilon/R)l = B((Bvl)/R)l`
`therefore F=((B^2v)/R)l^2`
`therefore F prop l^2` (`because` Remaining terms are constant)