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.

$A$ current-carrying conductor obeys Ohm's law $(V = RI)$. If the current passing through the conductor is $I = (5 \pm 0.2) \text{ A}$ and the voltage developed is $V = (60 \pm 6) \text{ V}$, then find the percentage error in resistance $R$.

Can error be completely eliminated?

$A$ student determined Young's Modulus of elasticity using the formula $Y = \frac{M g L^{3}}{4 b d^{3} \delta}$. The value of $g$ is taken to be $9.8 \, m/s^2$, without any significant error. His observations are as follows:

Physical Quantity	Least count and Observed value
Mass $(M)$	$1 \, g$ and $2 \, kg$
Length of bar $(L)$	$1 \, mm$ and $1 \, m$
Breadth of bar $(b)$	$0.1 \, mm$ and $4 \, cm$
Thickness of bar $(d)$	$0.01 \, mm$ and $0.4 \, cm$
Depression $(\delta)$	$0.01 \, mm$ and $5 \, mm$

Then the fractional error in the measurement of $Y$ is:

In an experiment of a simple pendulum,the time period measured was $50 \, s$ for $25$ vibrations when the length of the simple pendulum was taken as $100 \, cm$. If the least count of the stopwatch is $0.1 \, s$ and that of the meter scale is $0.1 \, cm$,then the maximum possible error in the value of $g$ is .......... $\%$

The length $l$,breadth $b$,and thickness $t$ of a block of wood were measured with the help of a measuring scale. The results with permissible errors are $l = 15.12 \pm 0.01 \; cm$,$b = 10.15 \pm 0.01 \; cm$,and $t = 5.28 \pm 0.01 \; cm$. The percentage error in volume up to proper significant figures is: (in $\%$)