# Internal resistance proportional to current?

1. Apr 3, 2015

### CAH

The terminal voltage and current are measured as the resistance is decresed through a cell with emf and internal resistance. Graph of V (y axis) I (x axis) shows straight line decreasing gradient.
1. Explain why terminal pd decreases as the current increases.

is terminal pd the same as pd/voltage? I thought the pd across a resistor would always be the same provided your not adding resistors. However the mark scheme says:

mention of pd across internal resistance or loss in internal resistance or emf>V,
pd across internal resistance/loss volts increases with current or correct use of equation to demonstrate

So does the internal resistance increase with the current and so voltage is lost through wires?

Thanks

2. Apr 3, 2015

### sophiecentaur

No. As with all resistances, the voltage dropped across it is proportional to the current and the internal resistance is usually assumed to be constant. That is a bit of an oversimplification for many components, though.

3. Apr 3, 2015

### CAH

so the voltage will continuously drop to internal resistance? It seems like a lot of volts lost just to internal resistance?

4. Apr 3, 2015

### sophiecentaur

IF the internal resistance is 1 Ohm then every Amp will cause a drop of 1 Volt. There's no surprise there.