Given data is insufficient. Are you sure you posted all the given quantities?Gustavs1337 said:Homework Statement
I need to calculate EMF and internal resistance from the given resistance and voltage.
R = 3 ohms
U = 3,6 V
EMF- ?
I0 - ?
r - ?
Homework Equations
I = U/R
EMF = A/q
I = EMF/R+r
I0 = EMF/r
The Attempt at a Solution
I = 3,6/3 = 1,2 A
I = EMF/R+r
1,2= EMF/3+r
^ I hit a wall there, don't know whether to consider EMF to be the same as Voltage or not. Help please.
There is a second measurement which is with a resistance of 5 and a voltage of 3,8. I am not sure if that helps. Also the electric circuit consists of a switch, battery, resistance and an internal voltmeter ( not sure about the internal part but it is on the inside of the circuit and not the outside).cnh1995 said:Given data is insufficient. Are you sure you posted all the given quantities?
Ok. Start by drawing a circuit diagram.Gustavs1337 said:Circuit consisting of battery, switch, resistance and a voltmeter. We take 2 measurements. One with a resistance of 3 ohms, there's voltage of 3.6 volts. Second with a resistance of 5, there's a voltage of 3.8 volts. Calculate the EMF, internal resistance and short-circuit current(sorry i didnt mention the short circuit current before)
You know R and I for two measurements. You havd two unknowns Emf and r.Gustavs1337 said:I = EMF/R+r
EMF stands for electromotive force and is the potential difference created by a battery or power source. Internal resistance is the resistance within the battery itself, which can cause a decrease in the EMF.
Internal resistance can cause a voltage drop within the circuit, leading to a decrease in the overall voltage and therefore a decrease in the circuit's performance. It can also lead to the battery heating up and decreasing its lifespan.
The internal resistance of a battery can be affected by its chemical composition, temperature, and age. Higher temperatures and older batteries tend to have higher internal resistance, leading to a decrease in performance.
One way to measure the internal resistance of a battery is by using a multimeter and measuring the voltage drop across a known resistor. The internal resistance can then be calculated using Ohm's law (R = V/I).
Internal resistance cannot be completely eliminated, but it can be reduced by using batteries with lower internal resistance or by using multiple batteries in parallel to decrease the overall internal resistance. However, this reduction may also lead to a decrease in the overall EMF of the circuit.