# Physical explanation of VI

1. Jul 27, 2017

### Cici2017

1. The problem statement, all variables and given/known data
Please provide a physics explanation of this question:
How does load current affect the potential difference across the terminals of a cell?

2. Relevant equations

3. The attempt at a solution
p.d. inversely proportional to current. Thus, when I increase, the p.d. decrease and vice versa

Is this a good enough 'physics explanation' for this question? Thanks~

2. Jul 27, 2017

### phinds

No, it is not because in an ideal power source it is not true so you need to explain why it IS true (and preferably also to what extent it is true) in a real power source.

3. Jul 27, 2017

### Cici2017

I don't know why is it true...

4. Jul 27, 2017

### Nidum

An ideal cell maintains terminal voltage independent of load current . In a real cell the terminal voltage drops as load current increases .

What common electrical component could you put in series with an ideal cell so that the ideal cell and the additional component together behave like a real cell ?

Edit : Haven't you essentially got the answer to this question in your previous posting?

Last edited: Jul 27, 2017
5. Jul 30, 2017

### David Lewis

Voltage times current gives power, but to answer this question, you'll need Ohm's Law.

6. Jul 30, 2017