Young's modulus is determined by the equation given by $\mathrm{Y}=49000 \frac{\mathrm{m}}{\mathrm{l}}…

Young's modulus is determined by the equation given by $\mathrm{Y}=49000 \frac{\mathrm{m}}{\mathrm{l}} \frac{\mathrm{dyn}}{\mathrm{cm}^2}$ where $M$ is the mass and $l$ is the extension of wire used in the experiment. Now error in Young modules $(Y)$ is estimated by taking data from $M-l$ plot in graph paper. The smallest scale divisions are $5 \mathrm{~g}$ and $0.02 \mathrm{~cm}$ along load axis and extension axis respectively. If the value of $M$ and $l$ are $500 \mathrm{~g}$ and $2 \mathrm{~cm}$ respectively then percentage error of $Y$ is :
  1. $0.5 \%$
  2. $2 \%$
  3. $0.02 \%$
  4. $0.2 \%$

Solution

$\begin{aligned} \frac{\Delta \mathrm{Y}}{\mathrm{Y}} & =\frac{\Delta \mathrm{m}}{\mathrm{m}}+\frac{\Delta \ell}{\ell} \\ & =\frac{5}{500}+\frac{0.02}{2}=0.01+0.01 \\ \frac{\Delta \mathrm{Y}}{\mathrm{Y}} & =0.02 \Rightarrow \% \frac{\Delta \mathrm{Y}}{\mathrm{Y}}=2 \%\end{aligned}$

Asked in: JEE Main 2024 (08 Apr Shift 1)

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