Light travels through air at 300 million $ms ^{-1}$. On entering water it slows down to 225 million $ms ^{-1}$. Calculate the refractive index of water.
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Speed of light in air = 300 million $ms ^{-1}$ Speed of light in water = 225 million $ms ^{-1}$ We know that,$\text{Refractive index of water}=\frac{\text{Speed of light in air}}{\text{Speed of light in water}}$
$\text{Refractive index of water}=\frac{300\text{ million m}/ \text{ s}}{225\text{million m}/\text{s}}=1.33$
$\text{Refractive index of water}=\frac{300\text{ million m}/ \text{ s}}{225\text{million m}/\text{s}}=1.33$
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