Huygens Principle (in Hindi)

Lesson 5 of 17 • 6 upvotes • 12:34mins

Rajesh Kumar

Huygens principle : Proposer of the wave theory of light . he considered light is a mechanical wave moving in a hypothetical medium known as Ether. hygens principle : various points of an orbital surface when reached by a wavefront become secondary sources of light emitting secondary wavelets the disturbance beyond the surface results from the superposition of these secondary wavelets . hygens construction: The geometrical envelope of secondary wavelets at any given later instant represents the new position of the wavefront at that instant it is valid for light waves. the surface used in the hygens construction may have any arbitrary shape. if medium is homogenous light moves forward and does not reflect back . if change in medium the wave maybe reflected from the discontinuity then secondary wavelets on the backside should also be considered . reflection of light: here AB is equal to the Wavefront of the incident light at time t is equal to zero .Sigma is equal to source of secondary wavelets V is equal to speed of light . incident ray perpendicular to a b and the normal is perpendicular to AC angle A is equal to angle BAC and angle R is equal to angle ACD. triangle ADC congruent triangle ABC. therefore angle BAC is equal to angle DCA this implies angle A is equal to angle r that is angle of incidence is equal to angle of reflection . incident ray ,reflected ray and normal all are in same plane that is coplanar which proof the reflection of light by hygens principle . refraction of light: a b is equal to incidentvwavefront CD is equal to secondary wavefront .sini is equal to bc by ac is equal to V1t divided by AC , sinr is equal V2t by AC, comparing this We get sin i / sinr is equal to V1 upon V2 that is known as snell’s law here V1 and V2 are speed of light in medium 1 and medium 2, the ratio of V1 and V2 known as refractive index of medium 2 with respect to medium 1 which is represented by Mu of 21 . if medium one is vacuum then mewtwo 1 is equal to move refractive index of medium to YouTube one is written in another format beauty divided by new one incident ray reflected ray and normal all are in same plane that is coplanar which proves the law of refraction of light by hygens principle. if medium one is a medium to is better than angle A is equal greater than angle R that is even greater than B to this is opposite to the prediction of the Newton’s corpuscular theory Newton says that when medium change then denser medium attract light particle that is denser medium speed of light is Greater.