What Is the Current Through a Resistor with Internal Battery Resistance?

[jimmyting]

[SOLVED] Battery with internal resistor

Homework Statement

What is the current in a 8.25 ohm resistor connected to a battery that has a .21 ohm internal resistance when the potential drop across the terminals of the battery is 6V?

Homework Equations

$$R_{s}=R_{1}+R_{2}...$$

$$V=IR$$

The Attempt at a Solution

So I believe that the internal resistor can just be considered being in series to the other resistor, allowing me to calculate the equivalent resistor. Then with that, using V=IR, I thought I was able to get the current flowing through the circuit. I got .70921 A
Can someone correct my train of thought?

 

[Hootenanny]

Homework Statement

What is the current in a 8.25 ohm resistor connected to a battery that has a .21 ohm internal resistance when the potential drop across the terminals of the battery is 6V?

Homework Equations

$$R_{s}=R_{1}+R_{2}...$$

$$V=IR$$

The Attempt at a Solution

So I believe that the internal resistor can just be considered being in series to the other resistor, allowing me to calculate the equivalent resistor. Then with that, using V=IR, I thought I was able to get the current flowing through the circuit. I got .70921 A
Can someone correct my train of thought?

Note that the potential drop across the terminals includes the internal resistance of the battery. The internal resistance of a battery may be depicted thus,

So the actual emf of the battery is the 6V plus the voltage drop across the internal resistance. Do you follow?

Image courtesy of Hyperphysics

 

[jimmyting]

Yes I do thank you for your help. Funny that you got the picture off hyperphysics, I was on there trying to read about this

 

[Hootenanny]

Yes I do thank you for your help.

No problem.

Funny that you got the picture off hyperphysics, I was on there trying to read about this

Hyperphysics is an excellent general physics reference, I'm glad that you chose to look there rather than Wikipedia