# Effect of wire heating on battery EMF

• Molly1235
In summary: Difficult to help without some more information. What is the context of this question/problem/exercise ?This question is asking for a solution to a problem, in which the student is trying to determine the effect of wire heating on the gradient of a line plotted between voltage and current. The student has attempted to find the answer by measuring V and I with meters, and found a straight line with a negative gradient. They are now trying to figure out the effect of the additional resistance of the wire heating on the gradient of the line.
Molly1235

## Homework Statement

I need to know what effect wire heating would have on the reading of the EMF of a battery, and how the heating effect can be reduced!

V= IR

## The Attempt at a Solution

Well I know that the heating effect increases the resistance in the wire but this is as far as I've got...as far as minimising the effect would a thicker wire work? As according to the resistivity equation a greater area results in less resistance...?

Difficult to help without some more information. What is the context of this question/problem/exercise ?

BvU said:
Difficult to help without some more information. What is the context of this question/problem/exercise ?

Ok, so we did a practical where we attached a rheostat to a cell, changing the resistance to get different values of I and V. We then plotted a graph of V (y axis) against I (x axis), the y intercept being E. I need to figure out the effect the additional resistance of the wire heating would have on the gradient of the line, thus the y intercept and value of E? I feel like I'm over complicating it but my head is super confused!

OK, so there are several wires involved: the connecting wires and the wire of the rheostat, to name a few.
I take it V and I were measured with meters, the V meter across the clamps of the battery and the I meter in series with the rheostat?
Did you get a straight line in the plot?
And: apparently there is an extra question about the effect of wires heating up. Which wires do you think are meant?

BvU said:
OK, so there are several wires involved: the connecting wires and the wire of the rheostat, to name a few.
I take it V and I were measured with meters, the V meter across the clamps of the battery and the I meter in series with the rheostat?
Did you get a straight line in the plot?
And: apparently there is an extra question about the effect of wires heating up. Which wires do you think are meant?

Yes the voltmeter was connected across the battery terminals and the ammeter in series. I got a straight line with a negative gradient...not sure which wires they're referring to as the question just asked me to talk about limitations and my teacher told us to talk about heating in wires. I'm assuming they mean the connecting wires though...

Well I know that the heating effect increases the resistance in the wire but this is as far as I've got...as far as minimising the effect would a thicker wire work? As according to the resistivity equation a greater area results in less resistance...?
Correct on three counts.
But if the voltmeter measures the voltage directly across the clamps of the battery, and the current meter at the same time measures the current actually delivered, the only wires that could disturb the situation would be wires inside the battery. The internal resistance, so to say. Which, along with the e.m.f. of the battery, is what your experiment is designed to determine.
From what you have described so far, you don't make use of the precise resistance of the rheostat, so it wouldn't matter if it heats up or not.

## 1. How does wire heating affect battery EMF?

When a wire is heated, it can increase the resistance in the circuit, causing a decrease in the battery's EMF (electromotive force). This is because the heat energy causes the atoms in the wire to vibrate more, which hinders the flow of electrons, resulting in a decrease in voltage.

## 2. Is the effect of wire heating on battery EMF significant?

The effect of wire heating on battery EMF can be significant, depending on the amount of heat and the type of wire used. In some cases, the decrease in EMF may be negligible, but in others, it can significantly impact the performance of the battery.

## 3. Can wire heating damage a battery?

Yes, wire heating can potentially damage a battery. If the wire becomes too hot, it can melt or even catch fire, which can damage the battery and surrounding components. Additionally, excessive heat can also cause the battery to overheat, reducing its lifespan.

## 4. How can I prevent wire heating from affecting battery EMF?

To prevent wire heating from affecting battery EMF, it is essential to use wires with a low resistance and a high heat tolerance. Additionally, proper insulation and spacing between wires can also help reduce the impact of wire heating on battery performance.

## 5. Are there any benefits to wire heating in a battery circuit?

In most cases, wire heating is undesirable in a battery circuit. However, in some cases, a small amount of wire heating can help regulate the temperature in the circuit, preventing the battery from overheating. This can be useful in certain applications, such as in electric vehicles.

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