An uniform electric field of strength \( E \) exists in a region. An electron of mass \( m \) en...

An uniform electric field of
strength \( E \) exists in a region. An
electron of mass \( m \) enters a point
\( A \) perpendicular to \( x \)-axis with
velocity \( V \). It moves through the
electric field and exits at point \( B \).
The components of velocity at \( B \)
are shown in figure. At \( B \) the \( y \)-component of velocity remain unchanged.
Find the rate of work done by the field at \( B \)
(1) \( \frac{2 m a^{2} V^{3}}{d^{3}} \)
(2) \( \frac{m a^{2} V^{3}}{2 d^{3}} \)
(3) \( \frac{4 m a^{2} V^{3}}{d^{3}} \)
(4) \( \frac{m a^{2} V^{3}}{d^{3}} \)