A) \[\text{1}.\text{5}\times \text{1}{{0}^{\text{8}}}\text{ m}/\text{s}\]
B) \[\text{2}\times \text{l}{{0}^{\text{8}}}\text{ m}/\text{s}\]
C) \[\text{3}\times \text{l}{{0}^{\text{8}}}\text{m}/\text{s}\]
D) \[\text{5}\times \text{l}{{0}^{\text{8}}}\text{m}/\text{s}\]
Correct Answer: A
Solution :
The critical angle is the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is \[{{90}^{o}}\]. \[_{1}{{n}_{2}}=\frac{1}{\sin C}\] ?. (i) Also, \[_{1}{{n}_{2}}=\frac{c}{v}\] ? (ii) From Eqs. (i) and (ii), we get v = c sin C Given, \[C={{30}^{o}}\], \[c=3\times {{10}^{8}}\,m/s\] \[\therefore \] \[v=3\times {{10}^{8}}\times \sin {{30}^{o}}\] \[v=3\times {{10}^{8}}\times 0.5\] \[=1.5\times {{10}^{8}}m/s\]You need to login to perform this action.
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