How to Calculate the Internal Resistance of a Battery?

[SJN]

Homework Statement

A torch bulb is marked 2.5V and 0.3A. When it is connected to a dry battery of e.m.f 3.0V the correct p.d of 2.5V is produced across it. Calculate the internal resistance if the battery.

Homework Equations

I=V/R?

The Attempt at a Solution

It's on paper - sorry!Answer = 1.67 - But how you get to that is the question - working out must be shown.

Thanks in advance,
Sam

 

[Hootenanny]

Answer = 1.67 - But how you get to that is the question - working out must be shown.

We do not provide solutions here. We will help you will your homework, but you have to show some effort first, by typing out your attempted solution for example.

The same goes for your other thread, "I don't know how to start" isn't an attempted solution.

 

[SJN]

OK Sorry,

It's just I tried to find my tutor today, and couldn't see him, so I'm a little puzzled.

Not to worry, have a good day.