# WAEC Physics Revision : How to Calculate E.M.F and Internal Resistance of a Circuit.

Example 1:. A cell has an internal resistance of 0.02 ohm and e.m.f of 2.0 volts. Calculate its Terminal Potential Difference if it Delivers (a) 5 A (b) 50 A

a. When the current is 5A, terminal Potential Difference, is 1.9volts solution in the image below

b. When the current is 50A, terminal Potential Difference, is 1.0volt solution in the image below

thus, the terminal potential difference decrease as the current drawn increases.

Example 1:. Ten 1.5 volts cells , each having an internal resistance of 0.2 ohm, are connected in series to a load of 58 ohms.

determine (a) the current flowing through the circuit and (b) the potential difference p.d at the terminals.

Diagram explanation. The battery has 10 cells.

Each cell, has an electromotive force of 1.5volts

Since all ten cells are connected in series, thus, the total e.m.f of the battery will be 10×1.5 which is 15 volts as you can see from the diagram above.

The battery has 10 cells. Each cell, has an internal resistance of 0.2 ohm.

Since all ten cells are connected in series, thus, the total internal resistance of the battery will be 10x 0.2 which is 2 ohms as you can see from the diagram above.

(a) the current flowing through the circuit when connected to a load of 50 ohms is 0.25A solution in the image below

(b) the potential difference p.d at the terminals, is 14.5 volts solution in the image below

You can check out the introduction to this very topic through this link, Physics : How to calculate the E.M.F and Internal Resistance of Battery

### Soft science hope to help raise the profile of science and show that physics, chemistry and Mathematics is not mystery but can be understood by everyone. Please follow if you wish to get the solutions and understanding to difficult topics in Chemistry, Physics and Mathematics. 08138624196 is my WhatsApp contact. Reach me for private tutorials for at very cheap fee.

Or you can follow, like , and share this post, my next article is on organic chemistry. let your friends be part of my next article coming tomorrow. Is organic chemistry time!!!

Mr Legit Source is a Computer Programmer. He loves computer programming and he is also a web designer and a developer. Mr Legit Source is a Senior Content Writer of Legitsource.com.ng

1. Like!! Really appreciate you sharing this blog post.Really thank you! Keep writing.

2. Hi,

I hope you are safe and well.

I am reaching to publish a guest post article on your website and will send you some topic ideas for that.

If my ideas interest you, I’ll send an article on any of the ones chosen by you. The article will be of great quality and is free of cost.

I would just need you to provide me a backlink within the main article.