Question

The photoelectric work function of copper is 4.7 eV. What are the threshold frequency and wavelength for photoemission from a copper surface? [1 eV = 1.6 × 10^-19 J]

(h = 6.63 × 10^-34 J∙s, c = 3 × 10⁸ m/s, 

e = 1.6 × 10^-19 J, 

m (electron) = 9.1 × 10^-31 kg)

Answer 1

Data : Φ = 4.7 eV, 1 eV = 1.6 × 10^-19 J, 

c = 3 × 10⁸ m/s, h = 6.63 × 10^-34 J.s

Threshold frequency, v₀ = \(\cfrac Φh\)

Threshold wavelength, \(\lambda_0\) = \(\cfrac{c}{v_0}\)