- Home
- Standard 11
- Physics
Young's modulus is determined by the equation given by $\mathrm{Y}=49000 \frac{\mathrm{m}}{\ell} \frac{\text { dyne }}{\mathrm{cm}^2}$ where $\mathrm{M}$ is the mass and $\ell$ is the extension of wre used in the experiment. Now error in Young modules $(\mathrm{Y})$ is estimated by taking data from $M-\ell$ 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 $\ell$ are $500 \mathrm{~g}$ and $2 \mathrm{~cm}$ respectively then percentage error of $\mathrm{Y}$ is :
$0.2 \%$
$0.02 \%$
$2 \%$
$0.5 \%$
Solution
$\frac{\Delta \mathrm{Y}}{\mathrm{Y}} =\frac{\Delta \mathrm{m}}{\mathrm{m}}+\frac{\Delta \ell}{\ell}$
$=\frac{5}{500}+\frac{0.02}{2}=0.01+0.01$
$\frac{\Delta \mathrm{Y}}{\mathrm{Y}} =0.02 \Rightarrow \% \frac{\Delta \mathrm{Y}}{\mathrm{Y}}=2 \%$
