Atoms Ques 24

24. The total energy of an electron in the first excited state of hydrogen atom is about -3.4 $eV$. Its kinetic energy in this state is

[2005]

(a) $3.4 eV$

(b) $6.8 eV$

(c) $-3.4 eV$

(d) $-6.8 eV$

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Answer:

Correct Answer: 24.(a)

Solution:

(a) K.E. $=\frac{Z^{2}}{n^{2}}(13.6 eV)$

Mechanical energy $=\frac{-Z^{2}}{n^{2}}(13.6 eV)$

$\therefore$ K.E. in 2 nd orbital for hydrogen

$=-$ Mechanical energy

$=\frac{(1)^{2}}{(2)^{2}}(13.6)=+3.4 eV$