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1.Units, Dimensions and Measurement
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A physical quantity $y$ is represented by the formula $y=m^{2}\, r^{-4}\, g^{x}\,l^{-\frac{3}{2}}$. If the percentage error found in $y, m, r, l$ and $g$ are $18,1,0.5,4$ and $p$ respectively, then find the value of $x$ and $p$.
A
$4$ and $\pm 3$
B
$5$ and $\pm 2$
C
$8$ and $\pm 2$
D
$\frac{16}{3}$ and $\pm \frac{3}{2}$
(JEE MAIN-2021)
Solution
$\frac{\Delta y}{y}=\frac{2 \Delta m}{m}+\frac{4 \Delta r}{r}+\frac{x \Delta g}{g}+\frac{3}{2} \frac{\Delta \ell}{\ell}$
$18=2(1)+4(0.5)+x p+\frac{3}{2}(4)$
$8=x p$
By checking from options.
$x=\frac{16}{3}, p=\pm \frac{3}{2}$
Standard 11
Physics
