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?

Explanation

When light travels through a distance x in a medium of refractive index `mu` its optical path is `mux`. Thus, if `mu` is the refractive index of glass,
`mu(2.00cm)=1.33xx(2.25cm)`
`or mu=1.33xx2.25/2.00=1.50`