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 .............. $\%$

In an experiment of a simple pendulum,the errors in the measurement of the length of the pendulum $(L)$ and time period $(T)$ are $3 \%$ and $2 \%$,respectively. The maximum percentage error in the value of $\frac{L}{T^2}$ is (in $\%$)

Time intervals measured by a clock give the following readings: $1.25 \; s, 1.24 \; s, 1.27 \; s, 1.21 \; s$,and $1.28 \; s$. What is the percentage relative error of the observations?

The temperatures of two bodies measured by a thermometer are $t_{1} = 20^{\circ}C \pm 0.5^{\circ}C$ and $t_{2} = 50^{\circ}C \pm 0.5^{\circ}C$. Calculate the temperature difference and the error therein.

$A$ cylindrical wire of mass $(0.4 \pm 0.01) \, g$ has length $(8 \pm 0.04) \, cm$ and radius $(6 \pm 0.03) \, mm$. The maximum error in its density will be $...... \, \%$.

$A$ person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is $\delta T = 0.01 \ s$ and he measures the depth of the well to be $L = 20 \ m$. Take the acceleration due to gravity $g = 10 \ ms^{-2}$ and the velocity of sound $v = 300 \ ms^{-1}$. Then the fractional error in the measurement,$\delta L / L$,is closest to: (in $\%$)