What is the frequency of radiation whose wavelength is 0.86 nm,?

The velocity of light is v = 3 x 10⁸ m/s.

The given wavelength is λ = 0.86 nm = 0.86 x 10⁻⁹ m.

Note that

v = fλ

where f = frequency.

Therefore

f = (3 x 10⁸ m/s) / (0.86 x 10⁻⁹ m)

= 3.488 x 10¹⁴ Hz

Answer: 3.49 x 10¹⁴ Hz