The resistance $R=V / I$ where $V=(100 \pm 5)\;V$ and $I=(10 \pm 0.2) \;A$. Find the percentage error in $R .$

A student performs an experiment for determination of $g \left(=\frac{4 \pi^{2} l }{ T ^{2}}\right), \ell =1 m$ and he commits an error of $\Delta \ell$. For $T$ he takes the time of $n$ oscillations with the stop watch of least count $\Delta T$ and he commits a human error of $0.1 s$ For which of the following data, the measurement of $g$ will be most accurate?

According to Joule's law of heating, heat produced $H = {I^2}\,Rt$, where I is current, $R$ is resistance and $t$ is time. If the errors in the measurement of $I, R$ and t are $3\%, 4\% $ and $6\% $ respectively then error in the measurement of $H$ is

In an experiment, the percentage of error occurred in the measurment of physical quantities $A, B, C$ and $D$ are $1 \%, 2 \%, 3 \%$ and $4 \%$ respectively. Then the maximum percentage of error in the measurement $X,$

where $X = \frac{{{A^2}{B^{\frac{1}{2}}}}}{{{C^{\frac{1}{3}}}{D^3}}}$, will be 

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?

What is estimation of error ? Write method for estimation.