An electron charge 1.6 x 10-19C is accelerated in vacuum from rest at zero volt towards a plate at 40k V. Calculate the kinetic energy of the electron
-
A.
4.0 x 10-26J -
B.
4.0 x 10-21J -
C.
6.4 x 10-20J -
D.
3.2 x 10-15J -
E.
2.5 x 10-20J
Correct Answer: Option D
Explanation
E = (frac{1}{2}QV = frac{1}{2} times 1.6 times 10^{-19} times 40000)
= 3.2 x 10-15J