In vacuum, the speed of light is c= 2.998 x 108m/s. However, the speed generally decreases when light travels through media other than vacuum. Then, the speed is approximately c divided by a quantity called the medium's refractive index (7). In which of the following, would the frequency of 210nm-light be the lowest? (c = 2v) (1) H2, n = 1.0001 (2) CCl4, n = 1.461 (3) H20, n = 1.3330 (4) silicone oil, n = 1.520 (5) diamond, n = 2.419

Light of wavelength 200 nm will have lowest frequency in while traveling through diamond.

Explanation:

Speed of the light in vacuum = c

Relation between speed of light , wavelength (λ) and frequency (ν);

Speed of light in a medium = c' = c/n

...[1]

Where : n = refractive index of a medium

So, the medium with greater value of refractive index lower the speed of light to greater extent.

From [1] , we can see that frequency of light is inversely proportional to the refractive index of the medium :

This means that higher the value of refractive index lower will be the value of frequency of light in that medium or vice-versa.

According to question, light of wavelength 200 nm will have lowest frequency in while traveling through diamond because refractive index of diamond out of the given mediums is greatest.

Increasing order of refractive indices:

Decreasing order of frequency of light 210 nm in these medium :

i belive it is water