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The speed of light in media `M_1` and `M_2` are `1.5 xx 10^8 m//s and 2.0 xx 10^8 m//s` respectively. A ray of light enters from medium `M_1` to `M_2` at an incidence angle `i`. If the ray suffers total internal reflection, the value of `i` is.A. Equal to `sin^(-1)((2)/(3))`B. Equal to or les than `sin^(-1)((3)/(5))`C. Equal to or greater than `sin^(-1)((3)/(4))`D. Less than `sin^(-1)((2)/(3))` |
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Answer» Correct Answer - C Refractive index for medium `M_(1)` si `mu_(1)=(c)/(V_(1))=(3 xx10^(8))/(1.5 xx10^(8))=2` Refractive index for medium `M_(2)` is `mu_(2)=(c)/(V_(2))=(3 xx 10^(8))/(2.0 xx 10^(8)) =(3)/(2)` For total internal reflection `sin I ge sin C` where `i=` angle of incidence `C=` critical angle But `sin C=(mu_(2))/(mu_(1))` `sin ge (mu_(2))/(mu_(1)) ge (3//2)/(2) rArr i gt sin^(-1)((3)/(4))`. |
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