Calculate EMF of Cell with 10 ohms & 15 ohms Resistors

  • Thread starter Chris-is-stuck
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EMF = 200 uA * 25 ohms = 5 mVIn summary, The conversation discusses calculating the EMF of a cell connected in series with a microammeter and two resistors. The total resistance is found to be 25 ohms and the current is 200 uA. The EMF is then calculated to be 5 mV.
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Chris-is-stuck
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hi I am sorry this is probably going to seem very easy to all you viewers but up to this point I've had to teach myself physics because i had no teacher. i still got a* at gcse though :tongue2:

the question is: A cell of negligible resistance is connected in a series with a microammeter of negligible resistance and two resistores of 10 ohms and 15 ohms. The current is 200 uA.

Calculate the EMF of the cell.

thanks a lot to anyone to helps me with this, cya later.


(jsut read rules sorry if I've broken any)
 
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  • #2
The total resistance is R=10+15=25 ohms. Therefore:

EMF = iR

You have i, so...
 

1. How do you calculate the EMF of a cell?

To calculate the EMF (electromotive force) of a cell, you will need to use the formula: EMF = V + Ir, where V is the voltage of the cell, I is the current flowing through the cell, and r is the internal resistance of the cell.

2. What is the significance of using 10 ohms and 15 ohms resistors?

The resistors are used to represent the internal resistance of a cell, which is a measure of the opposition to the flow of current within the cell. 10 ohms and 15 ohms are used as common values for resistors in circuits, and they can be used to calculate the EMF of a cell.

3. Can the EMF of a cell be negative?

Yes, the EMF of a cell can be negative if the voltage of the cell is less than the product of the current and internal resistance. This indicates that the cell is not able to generate enough energy to overcome the internal resistance and maintain a steady flow of current.

4. How does the EMF of a cell change with varying resistors?

The EMF of a cell will change with varying resistors, as it is affected by both the voltage and the internal resistance. As the resistance increases, the EMF will decrease, and as the resistance decreases, the EMF will increase.

5. What are some factors that can affect the accuracy of calculating the EMF of a cell?

Some factors that can affect the accuracy of calculating the EMF of a cell include the precision of the resistors used, the temperature of the cell, and any other sources of internal resistance in the circuit. It is important to use high-quality components and control for external factors to obtain an accurate measurement of the EMF.

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