MCQ
If separation between screen and source is increased by $2\%$ what would be the effect on the intensity
- AIncreases by $4\%$
- BIncreases by $2\%$
- CDecreases by $2\%$
- ✓Decreases by $4\%$
✓
Answer
Correct option: D.
Decreases by $4\%$
d
(d) $I \propto \frac{1}{{{r^2}}}$ ==> $\frac{{\Delta I}}{I} = - 2\frac{{\Delta r}}{r}$=$ - \,2 \times 2 = - \,4\,\% $
(d) $I \propto \frac{1}{{{r^2}}}$ ==> $\frac{{\Delta I}}{I} = - 2\frac{{\Delta r}}{r}$=$ - \,2 \times 2 = - \,4\,\% $
Hence intensity is decreased by $4\%.$
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