- #1

- 26

- 0

A battery whose emf is 3.0 V. and whose internal resistance is 0.70 ohms is connected to a circuit whose net resistance is 14.7 ohms. What is the terminal voltage of the battery?

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter sp1974
- Start date

- #1

- 26

- 0

A battery whose emf is 3.0 V. and whose internal resistance is 0.70 ohms is connected to a circuit whose net resistance is 14.7 ohms. What is the terminal voltage of the battery?

- #2

cepheid

Staff Emeritus

Science Advisor

Gold Member

- 5,192

- 38

- #3

- 26

- 0

Yeah but dont you use intermal resistance * ampere to figure a number for voltage and than take that and subtract from emf to figure terminal voltage?

- #4

cepheid

Staff Emeritus

Science Advisor

Gold Member

- 5,192

- 38

Yeah but dont you use intermal resistance * ampere to figure a number for voltage and than take that and subtract from emf to figure terminal voltage?

First of all, it's not "ampere." The name of the

Secondly, it is true that the voltage across the internal resistor will be the current through it multiplied by its resistance. The point I was trying to make was that it's okay that you haven't been given this current, because you can use Ohm's law for the whole circuit in order to

- #5

- 26

- 0

So 3.0V = I(R1 + R2)

3V = I (15.4) and than solve for I which would be .1948A?

3V = I (15.4) and than solve for I which would be .1948A?

- #6

cepheid

Staff Emeritus

Science Advisor

Gold Member

- 5,192

- 38

So 3.0V = I(R1 + R2)

3V = I (15.4) and than solve for I which would be .1948A?

Yeah, that's right.

- #7

- 26

- 0

But the question is asking for terminal voltage of the battery and this is in Ampere not volts.

- #8

cepheid

Staff Emeritus

Science Advisor

Gold Member

- 5,192

- 38

But the question is asking for terminal voltage of the battery and this is in Ampere not volts.

Yeah, but now that you have the current, you can do what you yourself suggested in post #3 in order to find the voltage across the internal resistor. It was a two-step problem. Do you understand? You needed to find the current through the circuit in order to find the voltage drop across the internal resistor.

- #9

- 26

- 0

sweet! 2.86V thanks!

Share: