Answer
(a) $6.58\times10^{14}\,Hz$
(b) $1.22\times10^{8}\,nm$
Work Step by Step
(a) $c=\nu\lambda$ where $c$ is the speed of light, $\nu$ is the frequency and $\lambda$ is the wavelength.
$\implies \nu=\frac{c}{\lambda}=\frac{3.00\times10^{8}\,m/s}{456\times10^{-9}\,m}=6.58\times10^{14}\,s^{-1}$
$=6.58\times10^{14}\,Hz$
(b) $\lambda=\frac{c}{\nu}=\frac{3.00\times10^{8}\,m/s}{2.45\times10^{9}\,s^{-1}}=0.122\,m=1.22\times10^{8}\times10^{-9}\,m$
$=1.22\times10^{8}\,nm$
