A metal rod of length I is moved with velocity v in a uniform magnetic field `vec B`. Emf is induced between the two ends of rod

Options

A. when `vec l` is parallel to `vec B`
B. when `vec l` is parallel to `vec v`
C. when `vec v` is parallel to `vec B`
D. none of the above cases

Answer

D

Explanation

Length, velocity and magnetic field should be mutually perpendicular, for emf to be induced or at least there should be mutually perpendicular components. Hence, option (d) is correct.