Abeam of light has a wavelength of 650 nm in vacuum. (a) what is the speed of this light in a liquid whose index of refraction at this wavelength is 1.47? (b) what is the wavelength of these waves in the liquid?

The speed of this light and wavelength in a liquid are and 442 nm.

Explanation:

Given that,

Wavelength = 650 nm

Index refraction = 1.47

(a). We need to calculate the speed

Using formula of speed

Where, n = refraction index

c = speed of light in vacuum

v = speed of light in medium

Put the value into the formula

(b). We need to calculate the wavelength

Using formula of wavelength

Where, = wavelength in vacuum

= wavelength in medium

Put the value into the formula

Hence, The speed of this light and wavelength in a liquid are and 442 nm.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.