Question

1 reractive index of a medium 'x' with respect to a medium y' is 2/3
and the refractive index of medium 'y' with respect to medium 'z' is 4/3.
find the refractive index of medium 'z' with respect to medium 'X'. If the
speed of light in medium 'x' is 3 x 108 ms-1, calculate the speed of light
in medium 'y'.
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Answer 1

Answer: Required refractive index is 9/8, speed of light in y is 2*10^8m/s

Explanation:

Note - Refractive Index 'n' with respect to 'o' = speed of o/speed of n.

Let speed of light in x be x' and speed of light in y be y'. So, y'/x'=2/3 -(1). Similary let speed of light in z = z'. So, z'/y'=4/3 -(2). {Given information in question}. Multiply (1) and (2), to get z'/x'=8/9. Reciprocating, x'/z'=9/8. This is the required refractive index.

We know, y'/x'=2/3. Substitute value of x', to get y'/3*10^8=2/3. So, y'=2*10^8 m/s.