Show your work. Show how you combine various resistors to get the total resistanceEitan Levy said:
I didn't think I should do this. Why is it wrong to just divide the voltage by the total current? This gives 4.2 instead of 4. We didn't study how to really combine the resistors when they are connected like this.phinds said:
You have computed something with the switch open and you are applying it when the switch is closed. That just flat does not work. You HAVE to figure out the combined resistance with the switch closed.Eitan Levy said:
What do you mean? These currents are for when the switch is CLOSED, not open.phinds said:
They how could you possibly have gotten it without combining the resistors?Eitan Levy said:
How do you know that the answer is 4Ω ? Was this a multiple choice question? Or perhaps they want the result rounded to an appropriate number of significant digits?Eitan Levy said:
I thought it doesn't matter how I reached those currents. I did combine the resistors in order to reach those current, and they are correct.phinds said:
Maybe they did but it would be very unusual. This is the answer written in the answers as correct.gneill said:
Eitan Levy said:
So you don't think you should combine the resistors but you did combine the resistors?Eitan Levy said:
This method is correct provided that your current values are correct. If, for correct current values, your result doesn't match the supplied answer for the total resistance with the appropriate number of significant figures for the given data, then that supplied "correct" value is not accurate.Eitan Levy said:
phinds said:
Alright, thanks for the help!gneill said:
Combined resistance in a circuit refers to the total resistance encountered by the flow of current through the circuit. It is calculated by adding all the individual resistances in a series circuit or by using the reciprocal method in a parallel circuit.
In a series circuit, combined resistance is calculated by simply adding all the individual resistances together. This is because the current has to pass through each component in succession, resulting in an additive effect on the total resistance.
In a parallel circuit, combined resistance is calculated using the reciprocal method. This involves finding the reciprocal of each individual resistance, adding them together, and then taking the reciprocal of the sum. This method takes into account the fact that the current is divided among the different paths in a parallel circuit.
When resistors are added in series, the combined resistance increases. This is because the current has to pass through each resistor in succession, resulting in an increase in the overall resistance encountered by the current.
When resistors are added in parallel, the combined resistance decreases. This is because the current is divided among the different paths, resulting in a decrease in the overall resistance encountered by the current.
