why does the potential difference between the terminals of a cell falls when the current is drawn from it in an external circuit?
Answers
Explanation:
A simplified way of thinking about a battery is that it produces positively charged ions on one plate called the anode, and negatively charged ions on the other plate called the cathode. There is a conductor called an electrolyte between the plates that conducts using the positive ions as charge carriers (instead of the electrons that we find in metal conductors). The positive ions in a Lithium ion battery are Lithium ions for example.
Now because opposite electrical charges attract each other, the positive ions are attracted to the negative ions on the cathode. The attraction pulls them to travel through the electrolyte. Their arrival at the cathode makes the cathode positively charged, and they leave behind a negative charge on the anode. It is this charge difference between the plates that drives current around the external circuit.