When light passes from air to a medium its speed reduces to 40%. The velocity of light in air is 3 × 108 ms-1. What is refractive index of the medium?

When light passes from air to a medium its speed reduces to 40%. The velocity of light in air is 3 × 108 ms-1. What is refractive index of the medium?

Ans: – We know, refractive index(u) = c/v,

Here, c= 3 × 10^8 m/s.

And, v= c × 40/100 = 1.2 × 10^8 m/s.

So, u= 3 × 10^8 / 1.2 × 10^8 = 5/2.

 

When sunlight is passed through prism, it splits into seven colours as shown in Fig. By numbers write corresponding colours.

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How do r and δ change for same angle of incidence i if the prism shown in Fig.is immersed in water

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Why does white light split into seven colours when it passes through a prism?

Ans: – The different colours or prism because of the all seven colours have different refractive index so when it passes through prism show this phenomenon.

Write a natural phenomenon of dispersion of light.

Ans: – Rainbow is the phenomenon of dispersion of light.

 

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