A) \[{{I}_{0}}\]
B) \[2\sqrt{5}{{I}_{0}}\]
C) \[2{{I}_{0}}\]
D) \[5\sqrt{5}{{I}_{0}}\]
Correct Answer: D
Solution :
The illuminance at B \[{{I}_{B}}=\frac{L}{{{1}^{2}}}\] .......(i) and illuminance at point C \[{{I}_{C}}=\frac{L\cos \theta }{(\sqrt{5{{)}^{2}}}}=\frac{L}{(\sqrt{5{{)}^{2}}}}\times \frac{1}{\sqrt{5}}\] \[\Rightarrow \ \ {{I}_{C}}=\frac{L}{5\sqrt{5}}\] ...... (ii) From equation (i) and (ii) \[{{I}_{B}}=5\sqrt{5}\ {{I}_{0}}\]You need to login to perform this action.
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