What is the relation between EMF and terminal potential?
Electromotive force (EMF) is equal to the terminal potential difference when no current flows. EMF and terminal potential difference (V) are both measured in volts, however they are not the same thing. EMF (ϵ) is the amount of energy (E) provided by the battery to each coulomb of charge (Q) passing through.
Why does a dead battery have high internal resistance?
As the battery is discharged the electrolyte concentration is reduced, becoming pure water when the battery is fully discharged. Because of this change in electrolyte concentration the battery resistance increases during discharge. Loss of electrolyte is also a frequent cause of increased electrolyte resistance.
Which battery will have a higher internal resistance?
Therefore, a typical alkaline AA battery may start out with an internal resistance of 0.15Ω but may increase to 0.75Ω when 90 percent discharged. The following is a list of typical internal resistances for various batteries….Battery Internal Resistance.
| Battery | Internal Resistance |
|---|---|
| AA alkaline | 0.15Ω |
| AA NiMH | 0.02Ω |
| D Alkaline | 0.1Ω |
| D NiCad | 0.009Ω |
What is the internal resistance of a real battery?
A common AA alkaline battery might have anywhere between 0.1 Ω and 0.9 Ω internal resistance.
What is the resistance of ideal voltmeter and why?
In an ideal situation, where the voltmeter is able to measure the actual potential difference across two points, there should be no current passing through it, and hence its resistance should be infinite. An ammeter is connected in series with a current carrying wire, to measure current passing through it.
What is the internal resistance of an ideal voltmeter what will happen if we connect it in series?
Answer: The internal resistance of an ideal voltmeter is infinity and the internal resistance of an ideal ammeter is zero. Ammeter is connected in series and voltmeter is connected in parallel with the electric appliance.
What should be the resistance of an ammeter?
The resistance of an ammeter should be low. An ammeter has to be connected in series with the circuit to measure current. In case, its resistance is not very low, its inclusion in the circuit will reduce the current to be measured. In fact, an ideal ammeter is one which has zero resistance.
Why does an ammeter have negligible resistance?
since ammeter has to be measure the current flowing in the circuit… And also it is connected in series therefore maximum amount of current should be passed through it therefore it has very low resistance….
Does a voltmeter have high resistance or low resistance?
A voltmeter measures the voltage difference between the two different points (say, on different sides of a resistor), but it should not change the amount of current going through the element between these two points. So it should have very high resistance so mat it doesn’t draw current through it.
Why voltmeter has high resistance give reason?
A voltmeter is always coonected in parallel across a device to measure the voltage across it. Hence, it has high resistance so that current flowing in the circuit would not disturbed and it can measure the correct value.
Should the resistance of an ammeter be high or low give reason?
How an ammeter can be changed into voltmeter?
Converting an ammeter to a voltmeter involves increasing the resistance of the ammeter. This is done by adding a high resistance in series with the ammeter. Let the range of the ammeter be 0 – I0 Amp and we convert it to a voltmeter of range 0 – V0 volt.