Structure of Atom - Result Question 31
####33. When an electron of charge ’ $e$ ’ and mass ’ $m$ ’ moves with a velocity ’ $v$ ’ about the nuclear charge ’ $Z e$ ’ in circular orbit of radius ’ $r$ ‘, the potential energy of the electrons is given by
[1994]
(a) $Z e^{2} / r$
(b) $-Z e^{2} / r$
(c) $Z e^{2} / r$
(d) $m v^{2} / r$
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Solution:
- (b) P.E. $=$ work done $=\int _{\infty}^{r}-\frac{Z e^{2}}{r^{2}} d r=-\frac{Z e^{2}}{r}$.
Kinetic and potential energy of atoms results from the motion of electrons. When electrons are excited they move to a higher energy orbital farther away from the atom. The further the orbital is from the nucleus, the higher the potential energy of an electron at that energy level. When the electron returns to a low energy state, it releases potential energy in the form of kinetic energy.
