  Question

(a) Define wavefront. Use Huygens' principle to verify the laws of refraction. (b) How is linearly polarised light obtained by the process of scattering of light ? Find the Brewster angle for air-glass interface, when the refractive index of glass =1.5.

Solution

(a) Wavefront : A wavefront is a continuous locus of all the particles of a medium which are vibrating in the same phase. In ΔAA′B,                    sin i=A′BAB             ...(i) In ΔAB′B,                    sin r=AB′AB             ...(ii) Dividing equation (i) by (ii),                            sin isin r=A′B/ABAB′/AB  sin isin r=A′BAB′           =ctvtsin isin r=cv=μ This is the law of refraction. (b) When a beam of white light is passed through a medium containing particles whose size is of the order of wavelength of light, then the beam gets scattered. When the scattered light is viewed through an analyser in a direction at the right angle to the direction of incidence, it is found to be plane polarised. This is called polarisation by scattering. We know that, tanip=μ⇒       tanip=1.5⇒       ip=tan−1(1.5)=56.31∘                                     Physics

Suggest Corrections  0  Similar questions
View More  People also searched for
View More 