Calculate Power Wasted in Cell: Help with EMF & Resistance

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In summary, a cell with an emf of 1.5V and internal resistance of 0.5 ohms is connected to a 2.5 ohm resistor. The current is calculated to be 0.5A and the terminal voltage is 1.25V. The power delivered to the resistor is also calculated. The next step is to find the power wasted in the cell. The equation Ie = I^2 + I^2r is used, where Ie represents the power supplied by the cell, I represents the current, and r represents the internal resistance. By rearranging and substituting the numbers, the amount of power wasted in the internal resistance can be determined. This concept is simpler than thinking
  • #1
ad_astra
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a cell of emf 1.5V and internal resistance 0.5 ohms is connected to a 2.5 ohm resistor.

ive calculated the current as 0.5A
terminal pd as 1.25V
and calculated the power delivered to the 2.5 ohm resistor.

now i have to calculate the power wasted in the cell?

ive got the equation Ie = I^2 + I^2r
which is the power supplied by the cell = the power delivered to R + the power wasted in the cell.

but I am so confused. on rearranging it and subsituting the numbers in?

can anyone shed any light on how i do this? and if so can you give me the equation and talk me through it please..

thanks :)
 
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  • #2
Hint:
How much power is dissipated in the internal resistance of the battery?

A battery can only generate power but a resistor can "waste" it.
 
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  • #3
ahh.. so i jus find out the amount of power delivered to the internal resistor and then that's my wasted power?
 
  • #4
Yes, that's right.

Asking it like that just turned a simple problem into a difficult one.
 

1. How do I calculate the power wasted in a cell?

To calculate the power wasted in a cell, you will need to know the EMF (electromotive force) and resistance of the cell. The formula for power is P=I*V, where I is the current and V is the voltage. To find the current, you can use Ohm's Law: I=V/R, where R is the resistance. Once you have the current and voltage, you can plug them into the power formula to calculate the power wasted in the cell.

2. What is EMF and how does it affect power wasted in a cell?

EMF stands for electromotive force, and it is the measure of the potential difference between two points in a circuit. In other words, it is the voltage produced by the cell. The higher the EMF, the higher the potential difference and therefore the higher the power wasted in a cell.

3. How does resistance impact power wasted in a cell?

Resistance is the measure of how much a material or component resists the flow of electricity. The higher the resistance, the lower the current and therefore the lower the power wasted in a cell. However, if the resistance is too high, it can cause the cell to overheat and potentially damage it.

4. Can power wasted in a cell be reduced?

Yes, power wasted in a cell can be reduced by either increasing the efficiency of the cell or by reducing the resistance in the circuit. This can be achieved by using higher quality materials, proper wiring and connections, and reducing the length of the circuit.

5. What are some common causes of power wasted in a cell?

Power wasted in a cell can be caused by a variety of factors, including high resistance in the circuit, using low quality materials, improper wiring and connections, and overloading the cell with too many devices. It can also be caused by internal factors such as internal resistance and chemical reactions within the cell.

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