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# The dissociation energy of $H_2$ is 430.53KJ. If $H_2$ is exposed to light energy of wavelength 253.7 nm , what $\%$ of light energy will be converted into kinetic energy?

$(a)\;91.2\%\qquad(b)\;93.5\%\qquad(c)\;90.5\%\qquad(d)\;92.6\%$

Energy associated with $H_2$ molecule corresponding to wavelength.
253.7 nm = $\large\frac{hc}{\lambda}$
$=\large\frac{6.63\times10^{-34}\times3\times10^8}{253.7\times10^{-9}}$
$=7.84\times10^{-19}J$
$=7.84\times10^{-19}\times6.02\times10^{23}$J/mol
$=472\times10^3$J/mol
$\%$ of light energy converted
$=\large\frac{430.53\times10^3}{472\times10^3}\times100$
$=91.2\%$