Question

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 :

• A. zero, if $v$ is vertical
• B. B${}_{0}lv$, if $v$ is verticaql
• C. zero, if $v$ is horizontal
• D. B${}_{0}lv$, if $v$ is horizontal

Answer 1

Answer: (A), (D)

The correct options are
A zero, if $v$ is vertical
D B${}_{0}lv$, if $v$ is horizontal

At north pole, $B$ is vertical.

If $v$ is vertical, then $v$ becomes parallel to $B$, hence no emf is generated.

If, $v$ is horizontal, then emf generated=$B_{0}lv$.

Hence, answers are option-(A) and (D).