A) 10 cm from 8 Cd lamp
B) 10 cm from 32Cd lamp
C) 40 cm from 8 Cd lamp
D) 40 cm from 32 Cd lamp
Correct Answer: C
Solution :
\[I=\frac{L}{{{r}^{2}}}\Rightarrow \frac{{{L}_{1}}}{{{L}_{2}}}=\frac{r_{1}^{2}}{r_{2}^{2}}\] or \[\frac{8}{{{x}^{2}}}=\frac{32}{{{(120-x)}^{2}}}\] Solving it we get\[x=40\,cm\].You need to login to perform this action.
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