Question 556: Current Electricity

Question

A potentiometer wire of length $$4 \mathrm{~m}$$ and resistance $$5 ~\Omega$$ is connected in series with a resistance of $$992 ~\Omega$$ and a cell of e.m.f. $$4 \mathrm{~V}$$ with internal resistance $$3 ~\Omega$$. The length of $$0.75 \mathrm{~m}$$ on potentiometer wire balances the e.m.f. of

Accepted Answer

$$	herefore \quad$$ Total Resistance:
$$\mathrm{R}=992+5+3=1000 \Omega$$
Voltage across $$4 \mathrm{~m}$$ wire:
$$\frac{5}{995+5} 	imes 4=0.02 \mathrm{~V}$$
$$	herefore \quad$$ For one metre wire:
$$\frac{0.02}{4}=0.005 \mathrm{~V}$$
$$	herefore \quad$$ For $$0.75 \mathrm{~m}$$ wire:
$$\begin{aligned}
0.004 	imes 0.75 & =0.00375 \
& =3.75 \mathrm{~mV}
\end{aligned}$$

Answer

4.00 mV

Answer

3.75 mV

Answer

3.00 mV

Answer

2.50 mV

Current Electricity

A potentiometer wire of length $4 \mathrm{~m} and resistance 5 ~\Omega is connected in series with a resistance of 992 ~\Omega and a cell of e.m.f. 4 \mathrm{~V} with internal resistance 3 ~\Omega. The length of 0.75 \mathrm{~m}$ on potentiometer wire balances the e.m.f. of

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