What is refractive index ?

Why is refractive index in a transparent medium greater that one?

What is the refractive index of water ?

Refractive index of glass relative to water is 9/8. What is the refractive index of water relative to glass? (AS_(1))

A light ray is incident on air-liquid interface at 45^@ and is refracted at 30^@. What is the refractive index of the liquud? For what angle of incidence will the angle between reflected ray and refracted ray be 90^@? (AS_(7))

A magician during a show makes a glass lens with n = 1.47 disappear in a through of liquid. What is the refractive index of the liquid ? Could the liquid be water ?

The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. If focal length is 12 cm. What is the refractive index of glass?

i. If f = 0.5 m for a glass lens, what is the power of the lens ? ii. The radii of curvature of the faces of a double convex lens are 10cm and 15cm . Its focal length is 12cm. What is the refractive index of glass ? iii. A convec lens has 20 cm focal length in air. what is focal length in water ? (Refractive index of air-water = 1.33, refractive index for air-glass = 1.5)

Light travels with a velocity 1.5xx10^(8)m//s in a medium. On entering 2^(nd) medium its velocity becomes 0.75xx10^(8)m//s . What is the refractive index of the 2^(nd) medium with respect to the first medium.