In an experiment,four quantities $a, b, c, d$ are measured with percentage errors $2\%$,$1\%$,$3\%$ and $5\%$,respectively. Quantity $P$ is calculated as $P = \frac{a^2 b^2}{c d}$. Find the percentage error in measuring $P$. (in $\%$)

Time for $20$ oscillations of a pendulum is measured as $t_1 = 39.6\, s$,$t_2 = 39.9\, s$,and $t_3 = 39.5\, s$. What is the precision in the measurements? What is the accuracy of the measurement?

$A$ metal wire has mass $(0.4 \pm 0.002) \, g$,radius $(0.3 \pm 0.001) \, mm$ and length $(5 \pm 0.02) \, cm$. The maximum possible percentage error in the measurement of density will nearly be $.......\%$

The current in a diode is given by the equation $I = (e^{1000V/T} - 1)$,where $V$ is the applied voltage in volts and $T$ is the absolute temperature in kelvin. $A$ student measures the current as $11 \text{ mA}$ at $300 \text{ K}$. If the error in measuring voltage is $\pm 0.01 \text{ V}$,the error in the value of current in $\text{mA}$ is:

$A$ capacitor of capacitance $(4.0 \pm 0.2) \mu F$ is charged to a potential of $(10.0 \pm 0.1) V$. The charge on the capacitor is

The unit of percentage error is