A glass slab of thickness `4 cm` contains the same number of waves as `5 cm` of water, when both are traversed by the same monochromatic light. If the refractive index of water is `4//3,` then refractive index of glass is

Options

A. `5//3`
B. `5//4`
C. `16//15`
D. `3//2`

Answer

A

Explanation

`""_(a)n_(g)=""_(a)n_(w)xx""_(a)n_(g)`
`""_(a)n_(g)=4/3xx(lamda_(w))/(lamda_(g))`
`""_(a)n_(g)=4/3xx5/4`
`""_(a)n_(g)=5/3`