How Do You Calculate the EMF of a Cell in a Circuit?

[oooouftt]

Finding the EMF of the cell...

first post =)

Homework Statement

Find the EMF of the cell.
(diagram has been uploaded)

Homework Equations

Resistors is series : Rs= R1 + R2 + R3
Resistors in parallel: 1/Rp = 1/R1 + 1/R2 + 1/r3
V=IR

The Attempt at a Solution

Firstly i re-drew the circuit in a more simple form, to see what resistors are in parralel and which ones are in series. I then found the total resistance in the parralel circuit part that contained the 0.2A current. after that i used : V=IR.
My answer still seems incorrect as i got total EMF = 4.8V

 

[Doc Al]

I then found the total resistance in the parralel circuit part that contained the 0.2A current. after that i used : V=IR.

That would tell you the voltage across that branch (and all parallel branches), but that's not the EMF of the battery.

Show exactly what you did, step by step.

 

[baba89]

As a scientist, it is important to approach problems with a critical and analytical mindset. In this case, it is crucial to gather all the necessary information and data before attempting to find the EMF of the cell. This includes understanding the circuit diagram and identifying the resistors in series and parallel, as well as their values.

Based on the given information, it seems that the student has correctly identified the resistors in series and parallel and has used the correct equations to find the total resistance in the parallel circuit. However, the calculation of the total EMF may be incorrect.

It is important to note that EMF (electromotive force) is the potential difference created by the cell, and it is equal to the voltage across the cell when there is no current flowing. In this case, the current flowing through the circuit is 0.2A, which means that there is a voltage drop across the resistors. Therefore, the total EMF of the cell cannot simply be calculated by multiplying the current by the total resistance.

To accurately calculate the EMF of the cell, it is necessary to use Kirchhoff's laws and Ohm's law to analyze the circuit and find the voltage across the cell. This may also require taking into consideration the internal resistance of the cell.

In conclusion, while the student has made a good attempt at finding the EMF of the cell, it is important to double-check the calculation and consider all the necessary factors to ensure an accurate answer.