(a) How is a rainbow formed ?
(b) Why do stars twinkle ?
(c) Why do the sky appear dark instead of blue to an astronaut ?
(a) Rainbow is formed when light passes through suspended water droplets in air
(b) Stars twinkle because Refractive indices of atmospher keep on changing due to which stars show twinkling effect
(c) Sky appear dark instead of blue to an astronaut because Scattering of light does not occur due to absence of medium in space.