The refractive index of water with respect to vacuum is 4/3 and refractive index of vacuum with respect to glass is 2/3. if the speed of light in glass is 2x 108m/s, find the speed of light in i) vacuum ii) water

As we know that refractive index of any medium with respect to vacuum is defined as

now its given that refractive index of vacuum with respect to glass is 2/3

Part (ii)

Now similarly we have

refractive index of water with respect to vacuum is 4/3

now we will have

i think the answer would be b

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