Question

A conducting rod held horizontally along East- West direction is dropped from rest from a certain height near the Earth’s surface. Why should there be an induced emf across the end of the rod? Draw a plot showing the instantaneous variation of emf as a function of time from the instant it begins to fall.

Answer 1

Emf induced due to change of magnetic flux across rod due to the presence of Earth’s magnetic field.

We know,

`E =(dphi_B)/(dt)`

As the Earth’s magnetic field is uniform,

`E =-Blv = -Bl (dx)/(dt)`

Hence,