A) 0.85
B) 0.49
C) 0.4
D) 0.3
Correct Answer: B
Solution :
\[{{\alpha }_{1}}=30{}^\circ ,\] \[{{(\eta b)}_{\max }}=\frac{2{{\cos }^{2}}{{\alpha }_{1}}}{1+{{\cos }^{2}}{{\alpha }_{1}}}\] \[=\frac{2{{\cos }^{2}}30{}^\circ }{1+{{\cos }^{2}}30{}^\circ }\] = 0.857You need to login to perform this action.
You will be redirected in
3 sec