Question

A conducting rod of length L is falling with velocity V in a uniform horizontal magnetic field B normal to the rod. The induced emf between the ends the rod will be :

• A. 2 BV$l$
• B. zero
• C. B$l$V
• D. $\frac{BVl}{2}$

Answer 1

The correct option is C B$l$V

Force on charge q due to the motion of rod in the field= $F=qVB$
This force on the charge is attributed to the induced electric field $E$
Therefore,
$Eq=F=qVB$
$E=VB$
therefore, an electric field $E=VB$ is said to be induced in the rod due to the motion in the magnetic field.
Potential difference due to the field = emf induced =$E\times length=El=VBlvolts$