A) \[40\sqrt{3}\]
B) 40
C) 20
D) \[40\times {{10}^{-7}}\]
Correct Answer: B
Solution :
Intensity of bulb \[I=\frac{L\cos \theta }{{{r}^{2}}}\] \[L=\frac{I\times {{r}^{2}}}{\cos \theta }=\frac{5\times {{10}^{-4}}\times {{(2\times {{10}^{2}})}^{2}}}{\cos {{60}^{o}}}\] \[L=40\,\,cd\]You need to login to perform this action.
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