Question

The energy of one mole of protons of radiation whose frequency is $5\times 10^{14}Hz$ is

• A. $192.51kJmo{l}^{-1}$
• B. $199.51kJmo{l}^{-1}$
• C. $195.45kJmo{l}^{-1}$
• D. $170.00kJmo{l}^{-1}$

Answer 1

Answer: (B)

Energy of one photon is
$E=hv$
$=6.626\times 10^{-34}Js\times 5\times 10^{14}Hz$
$=3.313\times 10^{-19}J$
$\because$ One mole photons contains
$=6.022\times 10^{23}$ photons.
For $1$ mole of photons, total energy
$=6.022\times 10^{23}\times 3.313\times 10^{-19}J/mol$
$=19.9508\times 10^{4}Jmo{l}^{-1}$
$=199.508\times 10^{3}Jmo{l}^{-1}$
$=199.508kJmo{l}^{-1}$