Answer
$1.1\times 10^{18}Hz$
Work Step by Step
We can find the required frequency as
$p=\frac{hf}{c}$
This can be rearranged as:
$f=\frac{pc}{h}$
We plug in the known values to obtain:
$f=\frac{1.37\times 10^{-27}\times 3\times 10^8}{6.63\times 10^{-34}}=1.1\times 10^{18}Hz$
