How do YOU understand electricity?

[luken93]

Electricity = Pikachu = Weird blue plasma that comes out of your body and can burn other people

haha, how does that help my understanding?

[the.watchman]

Well lets look at the first one (note: only voltage are measured parallel)

A: this is just across wires, so there would be no/minimal voltage drop

C: this is across a resistor, if the two resistors were the same (say 5ohm each), then the voltage drop across the resistor is half of the voltage which is 4.5V

D: again, if same resistor, then 4.5V drop

E: this is across both resistors, so the voltage drop over both is measured, so 9V

F: this is over wires, so no drop

V: the difference is 9V, as 9V is gained by the electrons thanks to the battery (sometimes not quite 9V, coz of the battery's internal resistance)

Hope this makes sense to you (try the other one yourself)

[luken93]

Okay so the second one
A: On the same wire with no resistance
=0V
B:All of the resistance is between these 2 points
=9V
C: Only encountering half of the resistance
=4.5V
D: No difference in between
=0V
E: Going from the positive to the negative end
=9V


So on the first one, if say
eg. First resistor was 10ohms and 2nd was 5hms
Would
C= 6V
D= 3V

or first resistor was 5ohms and 2nd was 10ohms,
C= 3V
D= 6V

Also, if both resistors were the same at say 10ohms, the amps would be.....




Is this right?

[kenhung123]

Only voltage is used up never current (charge)

[the.watchman]

Close, for Q2 (c), it should be 9V drop, as the current which flows through that path have ALL THEIR ENERGY USED UP, rather than half (the current splits, but their energy levels stay the same)

Otherwise good job!

(Note: In series circuits like Q1, the current is the same at any point, so yes you could work out the current that way, or just )

[kenhung123]

quick question; is pd energy per unit charge and emf if energy supplied to per unit charge?

[superflya]

quick question; is pd energy per unit charge and emf if energy supplied to per unit charge?

yes

[kenhung123]

How does that connect to parallel circuits having constant voltage?

[/0]

Well, as you reach a parallel junction, the electrons split into two paths.
However, voltage is not a property of the number of electrons. It is a property of the electrons themselves.

It's analogous to having athletes running along a track and splitting up at a parallel junction. As they go past the resistor, they each become fatigued and start breathing heavily. The voltmeter is like a measure of how fatigued the resistor made them. It doesn't measure how many athletes were running by.

[kenhung123]

Oh ok so resistance is the degree of tiredness?

[luken93]

Well, as you reach a parallel junction, the electrons split into two paths.
However, voltage is not a property of the number of electrons. It is a property of the electrons themselves.

It's analogous to having athletes running along a track and splitting up at a parallel junction. As they go past the resistor, they each become fatigued and start breathing heavily. The voltmeter is like a measure of how fatigued the resistor made them. It doesn't measure how many athletes were running by.

so is my teacher right in saying it is the amount of charge seperation between the 2 points (in this case before and after a resistor?)

[Blakhitman]

Electricity = Pikachu = Weird blue plasma that comes out of your body and can burn other people

YES, now I can get 40 SS with no study!

[/0]

Oh ok so resistance is the degree of tiredness?

Well, you could think of the voltage drop as making the electrons more tired (they still keep running though). It's just an analogy though.

Well, as you reach a parallel junction, the electrons split into two paths.
However, voltage is not a property of the number of electrons. It is a property of the electrons themselves.

It's analogous to having athletes running along a track and splitting up at a parallel junction. As they go past the resistor, they each become fatigued and start breathing heavily. The voltmeter is like a measure of how fatigued the resistor made them. It doesn't measure how many athletes were running by.

so is my teacher right in saying it is the amount of charge seperation between the 2 points (in this case before and after a resistor?)

I don't think it's the 'charge separation'. Since the number of electrons going into a resistor = number of electrons coming out of a resistor, and since each electron has a charge of which is constant, there shouldn't be a difference in charge before and after.

You can think of it as measuring the difference in the energy of the electron.

[luken93]

Oh ok so resistance is the degree of tiredness?

Well, you could think of the voltage drop as making the electrons more tired (they still keep running though). It's just an analogy though.

Well, as you reach a parallel junction, the electrons split into two paths.
However, voltage is not a property of the number of electrons. It is a property of the electrons themselves.

It's analogous to having athletes running along a track and splitting up at a parallel junction. As they go past the resistor, they each become fatigued and start breathing heavily. The voltmeter is like a measure of how fatigued the resistor made them. It doesn't measure how many athletes were running by.

so is my teacher right in saying it is the amount of charge seperation between the 2 points (in this case before and after a resistor?)

I don't think it's the 'charge separation'. Since the number of electrons going into a resistor = number of electrons coming out of a resistor, and since each electron has a charge of which is constant, there shouldn't be a difference in charge before and after.

You can think of it as measuring the difference in the energy of the electron.

ok that makes more sense now, so the greater the tiredness = the greater resistance they mustve faced.
so for my first picture, the first resistor essentially takes half of their energy, but the second resistor takes all of the energy that they have left in them?

[/0]

Yeah pretty much. They must lose all the energy they gained from the battery, so that when they reach the battery again they don't have leftover energy. The energy they lose in the resistor is also 'given' to the resistor, so the resistor might heat up (e.g. if it's a light globe)

(Really the 'energy' we are talking about here is their 'potential', but since 'potential' is just like energy per unit charge they're mostly the same thing)