In order to determine the frequency, we may use Planck's equation:
Energy = Planck's constant * frequency
Rearranging and substituting the values,
frequency = (1.8 x 10⁻¹⁵) / (6.63 x 10⁻³⁴)
f = 2.71 x 10¹⁸ Hz
The frequency of the light is 2.7 x 10¹⁸ Hz