Question

Find the speed of light in glass, if its absolute refractive index is 1.5. Also find the relative refractive index of glass with respect to water, if speed of light in water is 2.25x10⁸ m/s.(2+2=4)​

Answer 1

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$\boxed{Refractive \ index = \dfrac{spped\ in\ vaccum}{speed \ in \ medium}}$

where c= $3\times 10^8m/s$

$1.5= \dfrac{c}{v}$

$v= \dfrac {3\times 10^8}{1.5}= 2\times 10^8m/s$

• C is critical angle

$\boxed{n_{glass}\ sinC = n_{air} \ sin 90}$

$sinC= \dfrac {1}{n_{glass}}$

$sin C= \dfrac{1}{1.5}$

$C= 41.8$