Resistance and Voltage, switch diagram

AI Thread Summary
The discussion centers on understanding the relationship between resistance and voltage readings in a circuit. The initial assumption was that higher resistance would lead to higher voltage readings, but the correct order of voltage measurements contradicted this belief. It was clarified that the voltmeter measures the voltage drop across a single resistor, and the current through that resistor is influenced by the overall circuit resistance. The importance of considering the specific configuration and the fixed resistance of each resistor was emphasized. Ultimately, the participant gained insight into calculating voltage for individual resistors in different configurations.
vysero
Messages
134
Reaction score
0

Homework Statement


Untitled.png
[/B]
Untitled.png


Homework Equations


V=IR

The Attempt at a Solution


I said: A>D=F>B=C>G>H=E

I assumed higher resistance would lead to higher readings. However here are the answers:

H=E>C=B>G>D>F>A

Can someone explain to me why this is? As you can see H=E which combined gives a total resistance of (2/3)ohms is, according to the answers, going to give the largest volt meter reading. Why is this true?
 
Last edited by a moderator:
Physics news on Phys.org
vysero said:

Homework Statement


View attachment 80648
untitled-png.80648.png

Homework Equations


V=IR[/B]

The Attempt at a Solution


I said: A>D=F>B=C>G>H=E

I assumed higher resistance would lead to higher readings. However here are the answers:[/B]
Why assume that? The volt-meter only measures the voltage drop across that one resistor. Its resistance is fixed, so the voltage is proportional to the current through that resistor. Any current supplied by the battery must pass through that resistor, some how is that current related to the overall resistance of the circuit?

H=E>C=B>G>D>F>A

Can someone explain to me why this is? As you can see H=E which combined gives a total resistance of (2/3)ohms is, according to the answers, going to give the largest volt meter reading. Why is this true?
How do you get any particular resistance value?

No resistance value is given for any of the resistors. Are we to assume that they all have the same resistance?
 
SammyS said:
Why assume that? The volt-meter only measures the voltage drop across that one resistor. Its resistance is fixed, so the voltage is proportional to the current through that resistor. Any current supplied by the battery must pass through that resistor, some how is that current related to the overall resistance of the circuit?

How do you get any particular resistance value?

No resistance value is given for any of the resistors. Are we to assume that they all have the same resistance?

OH geesh sorry I feel like a dork I forgot a part of the question here is the explanation:

Untitled.png
 
vysero said:
OH geesh sorry I feel like a dork I forgot a part of the question here is the explanation:

View attachment 80652
untitled-png.80652.png

You could type some of this out.

Part of the explanation has been given. We need a response from you. You have over 100 posts, so you should know how things work here.

How did you arrive at your order? (in addition to having voltage behavior reversed.)
 
I am not sure how I had voltage behavior reversed. V = IR so and increase in resistance will increase voltage. If I = 1 and R = 4 then V = 4 if I = 1 and R = 10 then V = 10. 1<10

However, I did not take into account that the measurement of V was across only one resistor. I am currently trying to work out how to get the V for that one resistor in each configuration.
 
Thank you for the insight I understand now!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top