Question

The work function of sodium is 2.14 eV. What is the minimum frequency of a photon that will eject an electron from the sodium metal surface?

Answer 1

Ans :-

The minimum frequency of a photon that will eject an electron from the sodium metal surface is known as threshold frequency (v₀) .

As,

Work function = hv₀

Given, Work function = 2.14 eV = 3.424 x 10^-19 J , (as 1 eV = 1.6 x 10^-19 J)

Value of Planck's constant = h = 6.626176 x 10^-34 J.s

Therefore,

Work function = hv₀

3.424 x 10^-19 J = (6.626176 x 10^-34 J.s).(v₀)

v₀ = 3.424 x 10^-19 J / 6.626176 x 10^-34 J.s

v₀ = 5.167 x 10¹⁴ s^-1

Therefore, Threshold frequency or minimum frequency required to eject the electron = v0 = 5.167 x 1014 s-1