A photosensitive metallic surface has work function, h v₀ . If photons of energy 2 h v₀ fall on this surface, the electrons come out with a maximum velocity of 4 10^6 ~m / s . When the photon energy is increased to 5 h v₀ , then maximum velocity of photoelectrons will be

Step-by-step solution

The solution to our problem consists in Einstein's photoelectric equation. Einstein's photoelectric equation can be written as 1 2 m v^2=h v- 1 2 m (4 10^6 )^2=2 h v₀-h v₀...(i) and 1 2 m v^2=5 h v₀-h v₀...(ii) Dividing Eq. (ii) by Eq. (i), we get v^2 (4 10^6 )^2 = 4 h v₀ h v₀ array ll & v^2=4 16 10¹² & v^2=64 10¹² & v=8 10^6 ~m / s array NOTE: The efficiency of photoelectric effect is less than 1 % .ie, number of photons less than 1 % are capable of ejecting photoelectrons.