87) The band of the coloured components of a light beam is called its

A) refraction
B) dispersion
C) scattering
D) spectrum

88) The formation of a rainbow in the sky involves:

A) reflection, refraction, scattering
B) refraction, dispersion, reflection
C) refraction, scattering, dispersion
D) dispersion, total internal reflection, scattering

89) Advance sunrise and delayed sunset are due to

A) atmospheric refraction
B) atmospheric scattering
C) atmospheric dispersion
D) atmospheric reflection

90) The blue colour of clear sky is due to

A) dispersion of light
B) refraction of light
C) scattering of light
D) reflection of light

91) If the speed of light in glass is 2 × 10⁸m/s and the speed of light in air is 3×10⁸m/s, the refractive index of glass with respect to air is:

A) 6
B) 1
C) 1.5
D) 5