Question

Sodium street lamp gives of a characteristic yellow light of wavelenght 588 mm calculate the energy per mole of these photon

Answer 1

here λ = 580 nm(given)

We have to find out ν &  

Therefore from the equation  we can write,  

Where, ν = frequency of yellow light

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

λ = wavelength of yellow light = 580 nm = 580 × 10–9 m

Substituting the values in we get

Thus, frequency of yellow light emitted from the sodium lamp

= 5.17 × 1014 s–1

Wave number = it is defined as the number of wavelengths which can be accommodated in 1cm length along the direction of propagation.

Wave number of yellow light is given by the equation  

We have λ = 580 nm(given),putting the value in the equation  we get