The optical path of a monochromatic light is the same if it goes through 2.00 cm of glass or 2.25 cm of water. If the refractive index of water is 1.33, what is the refractive index of glass?

Options

A. `2.25 xx 10^(8)` m/s
B. `1.5 xx 10^(8)` m/s
C. `2 xx 10^(8)` m/s
D. `1.75 xx 10^(8)` m/s

Answer

C

Explanation

Optical path = `n xx ` distance travelled in the medium
`therefore n_(g) xx 2 = 2 .25 xx (4)/(3)`
`therefore n_(g) = 2.25 xx (4)/(3) xx (1)/(2) = 1.5`
` therefore V_(g) = (C)/(n_(g)) = (3 xx 10^(8))/(1.5) = 2 xx 10^(8)` m/s