Answer
a. $\lambda=1.318\times10^{-2}m$
b. $f=2.5\times10^{18}Hz$
Work Step by Step
a. Use equation 22–4, $c=\lambda f$.
$$\lambda=\frac{c}{f}=\frac{2.998\times10^8m/s }{22.75\times10^{9}Hz}$$
$$\lambda=1.318\times10^{-2}m$$
b. Use equation 22–4, $c=\lambda f$.
$$f=\frac{c}{\lambda}=\frac{3.00\times10^8m/s }{0.12\times10^{-9}m}$$
$$f=2.5\times10^{18}Hz$$