A person cannot see the distant objects clearly (though he can see the nearby objects clearly). He is suffering from the defect of vision called:

The size of the pupil of the eye is adjusted by:

The defect of vision in which the eye-lens of a person gets progressively cloudy resulting in blurred vision is called :

A man stands 10 m in front of a large plane mirror. How far must he walk before he is 5 m away from his image?

A ray of light strikes a plane mirror XY at an angle of incidence of 65°, is reflected from this plane mirror and then strikes a second plane mirror YZ placed at right angles to the first mirror. What is the angle of reflection for the mirror YZ?