Question 72: Current Electricity

Question

If voltage $$V=(200\pm 8)V$$ and current $$I=(20\pm0.5)A$$, then the percentage error in resistance R is

Accepted Answer

Voltage, $$V=(200\pm8)V$$
Current, $$I=(20\pm0.5)A$$
$$	herefore$$ Resistance, $$R = {V \over I} = {{200} \over {20}} = 10\,\Omega $$
Taking maximum error condition,
$${{\Delta R} \over R} = {{\Delta V} \over V} + {{\Delta I} \over I} = {8 \over {200}} + {{0.5} \over {20}} = {{13} \over {200}}$$
$$ \Rightarrow {{\Delta R} \over R} 	imes 100 = {{13} \over {200}} 	imes 100 = {{13} \over 2}\%  = 6.5\% $$

Answer

5.2%

Answer

25%

Answer

3%

Answer

6.5%

Current Electricity

If voltage $V=(200\pm 8)V and current I=(20\pm0.5)A$, then the percentage error in resistance R is

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