Name: Conversion of a Galvanometer Into a Voltmeter
Uploaded: 2019-07-19
Duration: 7 min 18 s
Description: This video helps us understand the working of a galvanometer. It also teaches us how to convert it into a voltmeter of the desired range both theoretically a...

Question

What is potential gradient? How is it measured? Explain.

Accepted Answer

The potential gradient is defined as the potential difference (the fall of potential from the high potential end) per unit length of the wire. In other words, it represents the slope along which potential is changing.

Let the length of potentithe ometer wire AB $= L$

Emf of the battery used in the potentiometer wire circuit $= ε$

Resistance from resistance box used in circuitthe , $= R$

Resistance of the wire AB $= r$

$∴$ Total rThe totalance of the circuit $= R + r$

Current in potentiometer wire, $i = \frac{ε}{R + r}$

Fall of potential across potentiometer wire, $i r = (\frac{ε}{R + r}) r$

Potential gradient $= \frac{f a l l o f p o t e n t i a l}{l e n g t h}$

$= (\frac{ε}{R + r}) \frac{r}{L}$

As we know that in the definition of potential gradient, we have two important factors which are, the potential difference and the length. So, to measure the potential gradient of a wire, first, we need to measure the potential difference between its end and then with the help of a measuring instrument, we have to precisely measure the length of the wire. Once we have done this, we will divide the potential difference by the length of the wire, and we will get the desired value of the potential gradient.

What is potential gradient? How is it measured? Explain.

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