$A$ body travels uniformly a distance of $(13.8 \pm 0.2) \text{ m}$ in a time $(4.0 \pm 0.3) \text{ s}$. Its velocity with error limits and percentage error is

Three students $S_{1}, S_{2}$ and $S_{3}$ perform an experiment for determining the acceleration due to gravity $(g)$ using a simple pendulum. They use different lengths of pendulum and record time for different number of oscillations. The observations are as shown in the table.

Student No.	Length of pendulum $(cm)$	No. of oscillations $(n)$	Total time for oscillations $(s)$	Time period $(s)$
$1.$	$64.0$	$8$	$128.0$	$16.0$
$2.$	$64.0$	$4$	$64.0$	$16.0$
$3.$	$20.0$	$4$	$36.0$	$9.0$

(Least count of length $= 0.1 \, cm$,least count for time $= 0.1 \, s$)
If $E_{1}, E_{2}$ and $E_{3}$ are the percentage errors in $g$ for students $1, 2$ and $3$ respectively,then the minimum percentage error is obtained by student no. ....... .

Calculate the mean percentage error in five observations: $80.0, 80.5, 81.0, 81.5, 82.0$. (in $\%$)

$A$ 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 $\%$)

The mass of an empty beaker is $(10.1 \pm 0.1) \, g$. When it is completely filled with a liquid,its mass becomes $(17.3 \pm 0.1) \, g$. What is the best value for the mass of the liquid within the possible limits of accuracy?

The percentage error in the measurement of a physical quantity $m$ given by $m = \pi \tan \theta$ is minimum when $\theta = \dots \dots \dots \dots \dots ^\circ$ (Assume that the error in $\theta$ remains constant).