Question

The photoelectric work function of a metal is 5.5 eV.Calculate the maximum speed of photoclectrons when clectromagnctic radiation with photon energy 5.8eV is incident on the surface of the metal.​

Answer 1

The maximum velocity of the electron = 3.24×10^5 m/s

We will use the Eienstien's photoelectric equation to find the speed of the electrons.

Equation - K.E (max) = (h × v) - φ

=> 1/2 mu² = Energy of photon - φ

K.E (max) - maximum kinetic energy of the electron

m - mass of the electron

u - the maximum velocity of the electron

φ - the work function of the metal = 5.5 eV

Energy of photon - 5.8 eV

1/2 mu² = 5.8 - 5.5 eV

=> 1/2 × 9.1 × 10^-31 × u² = 0.3 × 1.6 × 10^-19

=> u² = 0.105 × 10^12

=> u² = 10.5 × 10^10

=> u = 3.24×10^5 m/s

The maximum velocity of the electron= 3.24×10^5 m/s