51(1) Sunlight is composed of X-rays,visible light,UV-rays,infrared and radio waves.The violet,blue and indigo colors of light are of shorter wavelength, hence more scattered and absorbed in the atmosphere.White light devoid of violet,indigo and blue colors look yellow.
(2)The sunlit sky is blue because air scatters shorter wavelength light more than longer wavelengths.Since blue light is at the short wavelength end of visible spectrum,it is more strongly scattered in the atmosphere than long wavelength red light.The result is that the human eye perceives blue when looking towards parts of the sky other than the sun.The color perceived is similar to that obtained by monochromatic blue of wavelength 474-476 nm mixed with white light,i.e.,an unsaturated blue light.