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A voltmeter having a resistance of 998 ohms is connected to a cell of e.m.f. 2 volt and internal resistance 2 ohm. The error in the measurement of e.m.f. will be
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$4 \times 10^{-3}$ volt
Error in measurement $=$ Actual value Measured value
$\begin{aligned} & \text { Actual value }=2 \mathrm{~V} \\ & i=\frac{2}{998+2}=\frac{1}{500} \mathrm{~A}\end{aligned}$
Since $E=V+i r \Rightarrow V=E-i r=2-\frac{1}{500} \times 2=\frac{998}{500} \mathrm{~V}$
$\begin{aligned} & \therefore \text { Measured value }=\frac{998}{500} \mathrm{~V} \\ & \Rightarrow \text { Error }=2-\frac{998}{500}=4 \times 10^{-3} \mathrm{volt}\end{aligned}$
$\begin{aligned} & \text { Actual value }=2 \mathrm{~V} \\ & i=\frac{2}{998+2}=\frac{1}{500} \mathrm{~A}\end{aligned}$
Since $E=V+i r \Rightarrow V=E-i r=2-\frac{1}{500} \times 2=\frac{998}{500} \mathrm{~V}$
$\begin{aligned} & \therefore \text { Measured value }=\frac{998}{500} \mathrm{~V} \\ & \Rightarrow \text { Error }=2-\frac{998}{500}=4 \times 10^{-3} \mathrm{volt}\end{aligned}$
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