What is the fractional error in $g$ calculated from $T = 2\pi \sqrt {l/g}$? Given fractional errors in $T$ and $l$ are $\pm x$ and $\pm y$ respectively?

In an experiment to measure the height of a bridge by dropping a stone into water underneath,if the error in the measurement of time is $0.1\;s$ at the end of $2\;s$,then the error in the estimation of the height of the bridge will be (in $;m$)

$A$ student uses a simple pendulum of exactly $1 \ m$ length to determine $g$,the acceleration due to gravity. He uses a stopwatch with a least count of $1 \ s$ for this and records $40 \ s$ for $20$ oscillations. For this observation,which of the following statement$(s)$ is (are) true?
$(A)$ Error $\Delta T$ in measuring $T$,the time period,is $0.05 \ s$
$(B)$ Error $\Delta T$ in measuring $T$,the time period,is $1 \ s$
$(C)$ Percentage error in the determination of $g$ is $5 \%$
$(D)$ Percentage error in the determination of $g$ is $2.5 \%$

The potential difference across the ends of a conductor is $(30 \pm 0.3) \ V$ and the current through the conductor is $(5 \pm 0.1) \ A$. The error in the determination of the resistance of the conductor is: (in $\%$)

Zero error belongs to the category of

The mass and volume of a body are found to be $(5.00 \pm 0.05) \ kg$ and $(1.00 \pm 0.05) \ m^3$ respectively. Then the maximum possible percentage error in its density is .......... $\%$