Answer
(a) $3.46\times10^{-19}\,J$
(b) $2.09\times10^{5}\,J/mol$
Work Step by Step
(a) $E=h\nu=h\frac{c}{\lambda}$
$=6.626\times10^{-34}\,J\cdot s\times\frac{3.00\times10^{8}\,m/s}{574\times10^{-9}\,m}$
$=3.46\times10^{-19}\,J$
(b) $E=3.463\times10^{-19}\,J\times6.02214\times10^{23}/mol$
$= 2.09\times 10^{5}\,J/mol$
