Question

The relationship between kinetic energy (K) and potential energy (U) of electron moving in a orbit around the nucleus is

• A. $U = - K$
• B. $U = - 2K$
• C. $U = - 3K$
• D. $U = - \frac{1}{2}K$

Answer 1

Answer: (B)

$U = - 2K$

Answer 2

Kinetic energy $K = \frac{1}{2}mv^{2} = \frac{e^{2}}{8\pi\varepsilon_{0}r}$

And P.E. $U = - \frac{e^{2}}{4\pi\varepsilon_{0}r}$

Or $K = \frac{1}{2}mv^{2} = \frac{e^{2}}{8\pi\varepsilon_{0}r}$

$U = - 2K$