Dual Nature Of Light Question 220
Question: An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is [MP PMT 1993]
Options:
A) $ 5.9\times {{10}^{-4}}eV $
B) $ 5.9\times {{10}^{-6}}eV $
C) $ 5.9\times {{10}^{-8}}eV $
D) $ 11.8\times {{10}^{-6}}eV $ $ (h=6.62\times {{10}^{-34}}Js;\ \ c=3\times 10^{8}m/s) $
Show Answer
Answer:
Correct Answer: B
Solution:
$ E=\frac{hc}{\lambda }=\frac{3\times 10^{8}\times 6.62\times {{10}^{-34}}}{0.21\times 1.6\times {{10}^{-19}}}=5.9\times {{10}^{-6}}eV $
BETA
