The mass of an object is measured as $225 \pm 0.05 \, g$. Find the percentage error in this measurement. (in $\%$)

Write a note on the combination of errors.

$A$ quantity $P$ is related as $P = X^{-2}Y^{-3/2}Z^{2/5}$, where $X, Y, Z$ are independent parameters which have fractional errors of $0.1, 0.2$ and $0.5$ respectively in measurement. The maximum fractional error in $P$ is

The pressure on a square plate is measured by measuring the force acting on the plate and the length of the sides of the plate. If the maximum percentage error in the measurement of force and length are $4 \%$ and $2 \%$ respectively,what is the percentage error in the measurement of pressure (in $\%$)?

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. ....... .

$A$ quantity $Q$ is formulated as $Q = X^{-2} Y^{\frac{3}{2}} Z^{-\frac{2}{5}}$. $X, Y$ and $Z$ are independent parameters which have fractional errors of $0.1, 0.2$ and $0.5$,respectively,in measurement. The maximum fractional error of $Q$ is: