. The velocity of light in medium "A" and medium "B" are
"v." and ","respectively. What is the refractive index of medium “B” w.rt
medium "A"?
Answers
Answer:Absolute refractive index of a medium is defined as the ratio of the velocity of light in a vacuum to the velocity of light in the medium. If c is the velocity of light in vacuum and v in the medium, then: n = c/v Absolute refractive index = Speed of light in vacuum /Speed of light in medium According to question, For A, Speed of light in vacuum / Speed of light in medium A = na ..(i) For B, Speed of light in vacuum / Speed of light in medium B = nb ..(ii) Dividing (ii) by (i), nb /na=Speed of light in medium A/Speed of light in medium B Now, refractive index of medium 'B' with respect to medium 'A=Speed of light in medium A/Speed of light in medium B = nb/na = b/a Optical density of a medium is the measure of its transmittance for a radiation of particular wavelength. Higher is the value of optical density, lower is transmittance. it is expressed as log10 (1/T), where T is the transmittance in percentage (T = I/10). And also a higher value of refractive index means higher optical density. This means that light travels slower, in a medium with high optical density. Speed of light slows down in a optically denser because light interacts with the matter inside the denser medium.