Atoms - Result Question 39
41. When a hydrogen atom is raised from the ground state to an excited state,
[1995]
(a) P.E decreases and K.E. increases
(b) P.E. increases and K.E decreases
(c) both K.E. and P.E. decrease
(d) absorption spectrum
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Answer:
Correct Answer: 41. (d)
Solution:
- (b) P.E. $=-\frac{K Z e^{2}}{r}$ and $K . E .=\frac{K Z e^{2}}{2 r}$,
where, $r$ is the radius of orbit which increases as we move from ground to an excited state. Therefore, when a hydrogen atom is raised from the ground state, it increases the value of $r$. As a result of this, P.E. increases (decreases in negative) and K.E. decreases.
