A) 20
B) 30
C) 40
D) 50
Correct Answer: D
Solution :
By Snells law, \[\mu \sin \,i=\,\text{constant}\] \[\mu \,\sin i=(\mu -m\Delta \mu )\sin \,r\] Where \[\mu =1.5,\,i={{30}^{o}},\,r={{90}^{o}},\,\,\Delta \mu =0.015\] \[1.5\,\sin \,{{30}^{o}}=(1.5-m\times 0.15)sin{{90}^{o}}\] \[\frac{3}{2}\times \frac{1}{2}=(1.5-m\times 0.015)\times 1\] \[\frac{3}{4}=\frac{3}{2}-\frac{15m}{1000}\] \[15\,m=\left( \frac{3}{2}-\frac{3}{4} \right)\times 1000\] \[15\,m=\frac{6-3}{4}\times 1000\Rightarrow m=\frac{3}{4}\times \frac{1000}{15}\] \[m=\frac{3000}{60}\Rightarrow m=50\]You need to login to perform this action.
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