Question

Find energy of each of the photons which 

(i) Correspond to light of frequency 3 × 10¹⁵ Hz. 

(ii) have wavelength of 0.50 Å. 

Answer 1

(i) Energy (E) of a photon is given by the expression, 

E = hv 

Where, 

h = Planck‘s constant = 6.626 × 10^–34Js ν = frequency of light = 3 × 10¹⁵ Hz Substituting the values in the given expression of E: 

E = (6.626 × 10^–34) (3 × 10¹⁵) E = 1.988 × 10^–18J

(ii) Energy (E) of a photon having wavelength (λ)is given by the expression,

E = hc/λ

h = Planck‘s constant = 6.626 × 10^–34 Js 

c = velocity of light in vacuum = 3 × 10⁸ m/s 

Substituting the values in the given expression of E: