The magnitude of the earth's magnetic field at the north pole is `B_(0)` . A horizontal conductor of length `l` moves with a velocity `v` . The direction of `v` is perpendicular to the conductor. The induced emf is
(i) zero, if `v` is vertical
(ii) `B_(0)lv` , if `v` is vertical
(iii) zero, if `v` is horizontal
(iv) `B_(0)lv` , if `v` is horizontal

Options

A. (a) zero, if `v` is vertical
B. (b) `B_(0)lv`, if `v` is vertical
C. (c ) zero, if `v` is horizontal
D. (d) `B_(0)lv`, if `v` is horizontal

Answer

A, D

Explanation

(a,d):
At the poles, the earth's magnetic field is vertical.