Waves and photons

Exercise 3

The radioactive isotope $^{60}Co$ emits $\gamma$ photons at $1.887\cdot 10^{-13}J$. What is the wavelength of these photons?

$E_{photon}$ $=$ $h\nu$ = $1.887\cdot 10^{-13}J$ $\nu$ $=$ $\frac{E}{\nu}$ $=$ $\frac{1.887\cdot 10^{-13}}{6.626\cdot 10^{-34}}$ = $2.848\cdot 10^{20}Hz$ $\lambda$ $=$ $\frac{c}{\nu}$ $=$ $\frac{3\cdot 10^8}{2.848\cdot 10^{20}}$ = $1.053\cdot 10^{-12}m$