Calculate the maximum kinetic energy of photoelectrons emitted from this plate when light of wavelength (λ) 520nm is directed at the metal surface.

Work function (Ф) of the plate = 1.1 × 10⁻¹⁹ J
Planck's constant (h) = 6.63 × 10⁻³⁴ Js
Frequency (f) = c ÷ λ
c = speed light in vacuum = 3.00 × 10⁸ms⁻¹
Ekmax = hf - Φ

Wavelength must be in metres, so it'll be 590×10⁻⁹

I've worked this out and gotten two different answers so I thought I'd check to see which one is right.