Question

3 (i) The refractive indices of glass and water with respect to air are 3/2 and 4/3 respectively. If speed of light in glass is 2x108 m/s, find the speed of light in water.
(ii)Draw a ray diagram to show the principle focus of a convex mirror.​

Answer 1

Explanation:

(i) Given: Refractive index of glass with respect to air ng=3/2

 Refractive index of water with respect to air nw = 4/3

Speed of light in glass = 2 x 108m/s

 Applying the formula:

reflective index ng= speed of light in air /speed of light in water

3/2 =speed of light in air /2×10^8m/s

speed of light in air = 3× 10 ^8 m/s

similarly

reflective index nw =speed of light in air/ speed of light in water

4/3 = 3× 10 ^8/ speed of light in water

speed of light in water = 2.25 × 10^8 m/s

hope its help