Calculate the energy of electromagnetic waves of wavelength $3000\: A^{\circ}.$

Question

$\begin {array} {1 1} (a)\;18.4 \times 10^{-20}Wh & \quad (b)\;1.84 \times 10^{-20}Wh \\ (c)\;1.84 \times 10^{-22}Wh & \quad (d)\;18.4 \times 10^{-22}Wh \end {array}$