Q. An electron having charge *e* and mass *m* starts from the lower plate of two metallic plates separated by a distance d. If the potential difference between the plates is V, the time taken by the electron to reach the upper plate is given by

(a) $\Large \sqrt{\frac{2 m d^2}{e V}} $

(b) $ \Large \sqrt{\frac{ m d^2}{e V}} $

(c) $ \Large \sqrt{\frac{ m d^2}{2 e V}} $

(d) $ \Large \frac{2 m d^2}{e V} $

Ans: (a)