A) \[a=\frac{{{\lambda }^{2}}}{L}\]and\[{{b}_{\min }}=\sqrt{4\lambda L}\]
B) \[a=\frac{{{\lambda }^{2}}}{L}\]and\[{{b}_{\min }}=\left( \frac{2{{\lambda }^{2}}}{L} \right)\]
C) \[a=\sqrt{\lambda L}\]and\[{{b}_{\min }}=\left( \frac{2{{\lambda }^{2}}}{L} \right)\]
D) \[a=\sqrt{\lambda L}\]and\[{{b}_{\min }}=\sqrt{4\lambda L}\]
Correct Answer: D
Solution :
Spot size (diameter)\[b=2\left( \frac{\lambda L}{2a} \right)+2a\] \[{{a}^{2}}+\lambda L-ab=0\] ?(i) For Real roots \[{{b}^{2}}-4L\lambda \ge 0\] \[{{b}_{\min }}=\sqrt{4\lambda L}\]by eq. (i) \[a=\sqrt{\lambda L}\]You need to login to perform this action.
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