Does a flashlight battery have internal resistance?

[carnivalcougar]

Homework Statement

Does a flashlight battery have internal resistance? Explain.

Homework Equations

V = ε - Ir

The Attempt at a Solution

Yes, they do have internal resistance. This results in the open circuit ε being different than the voltage measured across the terminals if a current is drawn from the source.

I'm not sure why, though. I'm also not sure if the question is asking why they have internal resistance or if its just asking what the implications of this internal resistance are.

 

[berkeman]

Homework Statement

Does a flashlight battery have internal resistance? Explain.

Homework Equations

V = ε - Ir

The Attempt at a Solution

Yes, they do have internal resistance. This results in the open circuit ε being different than the voltage measured across the terminals if a current is drawn from the source.

I'm not sure why, though. I'm also not sure if the question is asking why they have internal resistance or if its just asking what the implications of this internal resistance are.

Yes, all real-life batteries and power supplies have internal series resistance. You can Google battery chemistry internal resistance to learn more to help you answer that part of the question.

 

[CWatters]

What he said.

Just about everything has resistance (except superconductors), including the terminals of the battery.

 

[rcgldr]

Although the term is internal resistance, part of this so called "resistance" is due to electro chemical factors, which reduce voltage output as current increases. Wiki article:

http://en.wikipedia.org/wiki/Internal_resistance#Batteries