Question

A current i, indicated by the crosses in figure, is established in a
strip of copper of height h and width w. A uniform field of magnetic
induction B is applied at right angle to the strip.
If the magnitude homogeneous electric field E be in order to counterbalance the effect of magnetic field is $E=2.8\times {10}^{-x}V{m}^{-1}$. Find x.

Answer 1

Force due to applied electric field should balance the magnetic force.

For this we have: $Ee=F$

$E=\frac{F}{e}=\frac{4.5\times {10}^{-23}}{1.6\times {10}^{-19}}=2.8\times {10}^{-4}V{m}^{-1}$ (in downward direction)