Light enters from air to kerosene having refractive index of 1.47. What is the speed of light in that medium?

A person cannot clearly see objects farther than 12 m from the eye. Name the defect in vision he is suffering from and the lens that should be used to correct this defect.

Explain the use of concave mirror as solar concentrators with the help of a ray diagram.

Murugan trims his beard while looking into a concave mirror whose focal length is

18 cm. He looks into it from a distance of 12 cm.

i) How far is Murugan’s image from the mirror?

ii) Does it matter whether or not Murugan’s face is closer or farther than the focal length? Explain.

Light travels at 1.90 x 10⁸ m/s in a crystal, what is the crystal’s index of refraction?