Modern Physics Ques 39
- In a $CO$ molecule, the distance between $C$ (mass $=12 $ $amu$ ) and $O$ $($ mass $=16 $ $amu)$, where $1 $ $amu=\frac{5}{3} \times 10^{-27}$ $ kg$, is close to
(a) $2.4 \times 10^{-10} $ $ m$
(b) $1.9 \times 10^{-10} $ $ m$
(c) $1.3 \times 10^{-10} $ $ m$
(d) $4.4 \times 10^{-11} $ $ m$
(2010)
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Answer:
Correct Answer: 39.(c)
Solution:
- $I=\mu r^{2}$ ( where, $\mu=$ reduced mass)
$ \mu=\frac{m _1 m _2}{m _1+m _2}=\frac{48}{7} amu=11.43 \times 10^{-27} kg $
Substituting in $I=\mu r^{2}$ we get,
$ \begin{aligned} r & =\sqrt{\frac{I}{\mu}}=\sqrt{\frac{1.87 \times 10^{-46}}{11.43 \times 10^{-27}}} \\ & =1.28 \times 10^{-10} m \end{aligned} $
BETA
