The ratio of thickness of plates of two transparent medium A and B is 6 : 4. If light takes equal time in passing through them, then refractive index of A with respect to B will be

Options

A. 1.4
B. 1.5
C. 1.75
D. 1.33

Answer

B

Explanation

Time = `("Distance")/("speed") = (nx)/(x ) " " ` [nx = constant ]
`therefore " " (n_(A))/(n_(B)) = (X_(B))/(X_(A))`
`rArr " " n_(BA) = (X_(A))/(X_(B)) = (6)/(4) = 1.5`.