## Answer :

Put that into the equations:

f = c/λ = 3.0 x10^8/5.2 ×10^-7 = 5.77 x10^14 (3 s.f.)

(5.77 x10^14) x (6.63 x10^-34) - (1.1 x10^-19) =

2.73 x10^-19 J

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.

Put that into the equations:

f = c/λ = 3.0 x10^8/5.2 ×10^-7 = 5.77 x10^14 (3 s.f.)

(5.77 x10^14) x (6.63 x10^-34) - (1.1 x10^-19) =

2.73 x10^-19 J