Question

The energy of one mole of photons of radiation of wavelength $300\, nm$ is
(Given : $h =6.63 \times 10^{-34} \,Js , N _{ A }=6.02 \times 10^{23}\, mol ^{-1}$, $c =3 \times 10^{8} \,ms ^{-1}$ )

• A. $235\, kJ \,mol ^{-1}$
• B. $325\, kJ \,mol ^{-1}$
• C. $399\, kJ\, mol ^{-1}$
• D. $435 \,kJ \,mol ^{-1}$

Answer 1

Answer: (C)

Energy of one mole of photons $=\frac{ hc }{\lambda} \times N _{ A }$
$=\frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{300 \times 10^{-9}} \times 6.02 \times 10^{23} $
$=399.13 \times 10^{3} $ Joule / mole
$=399\, $ kJ / mole