The working equation to solve this problem is written below:
E = hf,
where h is the Planck's constant = 6.626×10⁻³⁴ J·s
This equation is known as the Planck's equation.
Solving for the frequency,
f = E/h
f = 8.5×10⁻¹² J/6.626×10⁻³⁴ J·s
f = 1.282×10²² s⁻¹
