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1.Units, Dimensions and Measurement
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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
A
$ \pm 17\%$
B
$ \pm 16\%$
C
$ \pm 19\%$
D
$ \pm 25\%$
Solution
(b) $H = {I^2}R\,t$
$\therefore \,\,\,\frac{{\Delta H}}{H} \times 100 = \left( {\frac{{2\Delta I}}{I} + \frac{{\Delta R}}{R} + \frac{{\Delta t}}{t}} \right) \times 100$
$ = (2 \times 3 + 4 + 6)\% $ $ = 16\% $
Standard 11
Physics
