The refractive index of glass is `(3)/(2)` and the refractive index of water is `(4)/(3)` . The speed of light in glass is `2.00 xx 10^(8) ms^(-1)` . What is the speed of light in water in `ms^(-1)` ?

Options

A. `1.50 xx 10^(8)`
B. `2.25 xx 10^(8)`
C. `1.78 xx 10^(8)`
D. `2.67 xx 10^(8)`

Answer

B

Explanation

`""_(a) n_(g) = (C)/(v_(g)) therefore C = n_(g) xx v_(g)`
Similarly , `C = n_(w) xx v_(w)`
`therefore n_(w) xx v_(w) = n_(g) xx v_(g)`
`(4)/(3) xx v_(w) = (3)/(2) xx 2 xx 10^(8)`
`therefore v_(w) = 3 xx 10^(8) xx (3)/(4) = 2.25 xx 10^(8) ` m/s