Question

Calculate the the change in its potential energy of an electron in an atom which jumps in such a way that its kinetic energy changes from $x$ to $\frac{x}{9}$ .

• A. $\frac{x}{9}$ eV
• B. $\frac{16 x}{9}$ eV
• C. $9x$ eV
• D. $\frac{9}{16}$ eV

Answer 1

Answer: (B)

Change in kinetic energy

$x-\frac{x}{9}=\frac{8 x}{9}$

From Bohr's model of the atom:

The kinetic energy in a state is equal to half of the potential energy in magnitude.

$\therefore Potential \, energy$ $\left(P . E\right)$ Change

$=2 \, \times \, Kinetic \, energy \, \left(K . E\right)$ Change

$= \, 2 \times \frac{8 x}{9} \, \text{​} = \frac{16 x}{9} \, $ eV