Question-25 Calculate the energy per mole of photon of electromagnetic radiation having wavelength 700\ nm (h=6.626\times10^{-34}\ Js, c=3\times10^8\ m/s)
(A) 1.71\times10^5\ J
(B) 1.02\times10^5\ J
(C) 1.84\times10^5\ J
(D) 1.55\times10^5\ J
Answer : (A)
Explanation:
E = \frac{hc}{\lambda}
= \frac{6.626 \times 10^{-34} Js \times 3 \times 10^8 m/s}{700 \times 10^{-9} m}
= 2.839 \times 10^{-19} J
Energy per mole of photon
= 2.839 \times 10^{-19} \times 6.023 \times 10^{23} \approx 170992.97
= 1.71 \times 10^5 J