Q.No.106: - what is the relation between wave speed, refractive index, wavelength and the properties (condition) of medium. Explain.

Q.No.106: - what is the relation between wave speed, refractive index, wavelength and the properties (condition) of medium. Explain.

Ans: - If the medium is dense then wave speed then wave speed in this material will low as compared to wave speed in vacuum so the ratio of speed in vacuum over dense medium will be greater than unity. This ratio is refractive index.

                                n     =      c/v      =       vacuum/dense medium      >       1

or we can say that if refractive index is greater than unity then wave is passing through the denser medium where wave speed is less than as in vacuum.

         As,                             v        =         f.λ

Frequency remains same in every material. So velocity v is directly proportional to λ (lambda) wavelength. So if speed of wave changes then wavelength also changes. On the other hand if refractive index also depends upon wavelength. So we can say that in denser medium wave speed decrease so wavelength also decrease (shorter or squeezed).