A) increase by 1%
B) increase by 2%
C) increase by 4%
D) not change
Correct Answer: C
Solution :
When wire is stretched, its mass remains same. In that case \[A\times l\] is a constant \[R\propto {{L}^{2}}\propto \frac{1}{{{A}^{2}}}\propto \frac{1}{{{r}^{4}}}\]or \[R\propto {{r}^{-4}}\] Now, for small changes in\[r\], \[%\] change in \[R=(-4)%\]change in\[r\] In the given problem, \[%\] change in\[r=-1\] So, \[%\Delta R=(-4)\times (-1)=+\,\,4\]
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