A) \[{{(17/13)}^{3/2}}\]
B) 2 / 1
C) 17 / 13
D) 5 / 4
Correct Answer: A
Solution :
The illuminance at A is \[{{I}_{A}}=\frac{L}{{{(\sqrt{13})}^{2}}}\times \cos {{\theta }_{1}}=\frac{L}{13}\times \frac{3}{\sqrt{13}}=\frac{3L}{{{(13)}^{3/2}}}\] The illuminance at B is \[{{I}_{B}}=\frac{L}{{{(\sqrt{17})}^{2}}}\times \cos {{\theta }_{2}}\] \[=\frac{L}{17}\times \frac{3}{\sqrt{17}}=\frac{3L}{{{(17)}^{3/2}}}\] \[\therefore \] \[\frac{{{I}_{A}}}{{{I}_{B}}}={{\left( \frac{17}{13} \right)}^{3/2}}\]You need to login to perform this action.
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