Question

The ratio of the kinetic energy to the total energy of an electron in Bohr orbit is

• A. 1 : -1
• B. - 1 : 1
• C. 1 : 2
• D. 2 : -1

Answer 1

Answer: (A)

1 : -1

Answer 2

K.E. of electron in Bohr orbit, K = $\frac{1}{2} \frac{ke^2}{r}$
P.E. of electron in Bohr orbit, P.E. = - $\frac{ke^2}{r}$
$\therefore$ Total energy, E = K.E. + P.E = $\frac{1}{2} \frac{ke^2}{r} - \frac{ke^2}{r} = -\frac{1}{2} \frac{ke^2}{r}$
$\therefore$ $\frac{K.E.}{E} = \frac{\frac{1}{2} ke^2}{- \frac{1}{2} ke^2} = \frac{1}{-1}$
$\therefore$ K.E. : E = 1: -1