AP EAMCET · Chemistry · Structure of Atom
The energy of an electromagnetic radiation is \(19.875 \times 10^{-13}\) ergs. What is its wave number in \(\mathrm{cm}^{-1}\) ? \(\left(h=6.625 \times 10^{-27}\right.\) erg sec, \(\left.c=3 \times 10^{10} \mathrm{~cm} \mathrm{sec}^{-1}\right)\)
- A \(1000\)
- B \(10^6\)
- C \(100\)
- D \(10000\)
Answer & Solution
Correct Answer
(D) \(10000\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & E=h v=h \times \frac{c}{\lambda}=h \times c \cdot \bar{v} \\ & \therefore \quad \bar{v}=\frac{E}{h c}=\frac{19.875 \times 10^{-13}}{6.625 \times 10^{-27} \times 3 \times 10^{10}}=10^4\end{aligned}\)
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