Human Eye and C...

A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his text book. Which of the following statements is correct?

At noon the sun appears white as

Which of the following phenomena of light are involved in the formation of a rainbow?

Twinkling of stars is due to atmospheric

The clear sky appears blue because

Which of the following statements is correct regarding the propagation of light of different colours of white light in air?

The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

The bluish colour of water in deep sea is due to

When light rays enter the eye, most of the refraction occurs at the

The focal length of the eye lens increases when eye muscles

Which of the following statement is correct?