is the ratio of frequinces of uv rays and infrared rays in glass more than,less than or equal to 1?

On getting refracted , the frequency of light does not change where as there is a corresponding change in wavelength and speed of light. We also know that uv and infra red rays are part of light which is not visible to us.

Now ,when light passes through glass , the frequency wont change as a result , the ratio of frequencies of uv and infra red will be = 1

Dispersive power of the prism is given by the formula

ω = (μ_{v} – μ_{r})/(μ – 1)

here μ – 1 is the mean deviation. Also we can take μ with respect to yellow light as it is midway in the VIBGYOR series. μ_{v} and μ_{r }are the refractive index of prism for violet and red colours respectively.

Now, when the prism is immersed in water,each of the refractive indices in the above equation will be divided by refractive index of water. Hence numerator will reduce almost by a constant factor. However such will not be the case for denominator.

Hence the denominator will reduce less , as a result , when immersed in water, the dispersive power of the prism increases.

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