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Question: Answered & Verified by Expert
A 2 V battery, a $15 \Omega$ resistor and a potentiometer of $100 \mathrm{~cm}$ length, all are connected in series. If the resistance of potentiometer wire is $5 \Omega$, then the potential gradient of the potentiometer wire, is
PhysicsCurrent ElectricityVITEEEVITEEE 2011
Options:
  • A $0.005 \mathrm{~V} / \mathrm{cm}$
  • B $0.05 \mathrm{~V} / \mathrm{cm}$
  • C $0.02 \mathrm{~V} / \mathrm{cm}$
  • D $0.2 \mathrm{~V} / \mathrm{cm}$
Solution:
2334 Upvotes Verified Answer
The correct answer is: $0.005 \mathrm{~V} / \mathrm{cm}$
Potential gradient $\frac{d v}{d x}=\frac{e}{\left(R+R_{h}+r\right)} \cdot \frac{R}{L}$
$$
\begin{array}{l}
=\frac{2}{(15+5+0)} \times \frac{5}{1}=0.5 \mathrm{~V} / \mathrm{m} \\
=0.005 \mathrm{~V} / \mathrm{cm}
\end{array}
$$

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