Terminal voltage and current

  • #1
A battery has a terminal voltage of 12.0 V when no current flows. Its internal resistance is 2.0 Ω. If a 1.7 Ω resistor is connected across the battery terminals, what is the terminal voltage and what is the current through the 1.7 Ω resistor?

Can someone point me in the right direction?
I know I have to use V = E - Ir because there is a internal resistance.
But I am not sure how to start...

Thanks in advance.
Physics news on Phys.org
  • #2
Treat the internal resistance as a series resistor, find the total circuit current.

What is the voltage drop across the internal resistance? What do you think that will do to the terminal voltage?
  • #3
The terminal voltage is less than the emf because there is a voltage drop across the internal resistance.

I am still confused.
Last edited:
  • #4
As said earlier treat internal resistance as a series resistor

net resistance= R+r = 2+1.7

current= E/R = 12/3.7

terminal voltage = E - Ir
  • #5
thank you so much!

Suggested for: Terminal voltage and current