$A$ body travels uniformly a distance of $(13.8 \pm 0.2) \ m$ in a time $(4.0 \pm 0.3) \ s$. The percentage error in velocity is ......... $\%$

$A$ physical quantity $P$ is given by $P = \frac{A^3 B^{1/2}}{C^{-4} D^{3/2}}$. The quantity which brings in the maximum percentage error in $P$ is

$A$ physical quantity $X$ is related to four measurable quantities $a$,$b$,$c$,and $d$ as $X = a^2 b^3 c^{5/2} d^{-2}$. The percentage errors in the measurement of $a$,$b$,$c$,and $d$ are $1\%$,$2\%$,$3\%$,and $4\%$ respectively. The percentage error in the measurement of quantity $X$ is: (in $\%$)

$A$ 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?

In an experiment for determination of the focal length of a thin convex lens,the distance of the object from the lens is $10 \pm 0.1 \text{ cm}$ and the distance of its real image from the lens is $20 \pm 0.2 \text{ cm}$. The error in the determination of focal length of the lens is $n \%$. The value of $n$ is. . . . . . .

When two resistors of resistances $R_1=(200 \pm 2) \Omega$ and $R_2=(400 \pm 4) \Omega$ are connected in series,then the equivalent resistance of the combination is