The relative error in the determination of the surface area of a sphere is $\alpha$. Then the relative error in the determination of its volume is

Two students $P$ and $Q$ perform an experiment to verify Ohm's law for a conductor with resistance $R$. They use a current source and a voltmeter with least counts of $0.1 \, mA$ and $0.1 \, mV$,respectively. The plots of the variation of voltage drop $V$ across $R$ with current $I$ for both are shown below. Which statement is most likely to be correct?

$A$ student performs an experiment for the determination of $g = \frac{4 \pi^{2} \ell}{T^{2}}$. Given $\ell = 1 \, m$,the student commits an error of $\Delta \ell$. For $T$,the student measures the time of $n$ oscillations using a stopwatch with a least count of $\Delta T$ and commits a human error of $0.1 \, s$. For which of the following data will the measurement of $g$ be the most accurate?

$A$ physical quantity $x$ is related as $x = \frac{\sqrt{a}b^3}{c^4d^{-4}}$. Relative errors in the quantities $a, b, c$ and $d$ are $2\%, 1\%, 3\%$ and $4\%$ respectively. The relative error in $x$ will be: (in $\%$)

If there is a positive error of $50\%$ in the measurement of velocity of a body,then the error in the measurement of kinetic energy is .............. $\%$

The unit of percentage error is