If the critical angle for total internal reflection, from a medium to vacuum is `30^(@)`, then velocity of light in the medium is
If the critical angle for total internal reflection, from a medium to vacuum is `30^(@)`, then velocity of light in the medium is
A. `6 xx 10^(8) m//sec`
B. `3 xx 10^(8) m//sec`
C. `2 xx 10^(8) m//sec`
D. `1.5 xx 10^(8) m//sec`
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Correct Answer - D
`c = 30^(@), v_(m) = ?`
`._(m)mu_(a) = sin c = (v_(m))/(v_(a))`
`:. v_(m) = v_(a) xx sin c`
`= 3 xx 10^(8) xx sin 30`
`= 1.5 xx 10^(8) m//s`
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