How do YOU understand electricity?

[kenhung123]

What is current all about? The number of electrons?

[Blakhitman]

Current is the amount of Charge (coloumbs) passing a point per second.

And in one coloumb of charge there are 6.25x10^18 electrons.

[kenhung123]

So can you also say number of electrons passing a point per second?

[Blakhitman]

Well yea, but it's a specific number of electrons passing a point every second...6.25x10^18 (six million million million).

EDIT: if you mean define current as "number of electrons passing a point every second" then no, as current is no. of charge passing a point every second, as is seen in this formula where I= current, Q=Charge (in coloumbs) and T=Time in Seconds.

[/0]

Where N is the number of electrons passing the point and is the charge of an electron.

So yeah at least it's proportional to the number of electrons:

[kenhung123]

Thanks so much guys I finally understand electricity

[luken93]

Thanks so much guys I finally understand electricity

+1

[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 for C, is it 9V (thats what the.watchan said) because they will both be as tired whichever way they go?

[kenhung123]

Electricity is kinda fun now. Its like solving puzzles lol

[physics]

i dont D: its too hard grrrr and its only 4.1

[rashmi_34]

(Image removed from quote.)

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 for C, is it 9V (thats what the.watchan said) because they will both be as tired whichever way they go?

The voltage across "c" is still actually 9V; this is common for all parallel circuits (i.e.current does not loose voltage when it splits into branches)

the only thing that changes is the current, AND the current actually encounters TWICE the resistance in each branch, as opposed to considering this circuit as a series circuit with one resistor.
the effect of using resistors in parrallel reduces the total resistance of the circuit (in parallel circuits total resistance always has resistance lower than the branch with the lowest resistance).
Additionally, if resistance of each branch is the same then the total resitance is half the resistance of either branch. (this can be proved with the parralel circuit resistance equation)

IN a nutshell,
I-charge flowing in the circuit (current) splits into either one of two branches (current in each branch is half the total current of the circuit if you assume that both resistors are the same)
R-resistance of each branch is twice the value of total resistance if resistors are the same(you can check this with the parallel circuit resitance equation if you want to)
V-across each resistor is 9V (this piece of knowledge is vital as VCAA wants you to know this WITHOUT the use of equations; this is important as they will usually give you R and ask you to calculate I which will require you to use V)

if you want to you can also prove all this with V=IR

hope this has helped you

[physics]

i\m still kinda confused on whether we talk about the electrons flow or the current. i think current but then if i get that then i still dont get the cathode and anode thingos its too confusing :S physics will be my downfall D:

[rashmi_34]

i\m still kinda confused on whether we talk about the electrons flow or the current. i think current but then if i get that then i still dont get the cathode and anode thingos its too confusing :S physics will be my downfall D:

Heya,
I think the best way to look at this is:
rate at which charge/electrons flow=current
Either of these are interchangable in answering questions within the exam
unless the question specifies to mention current or charge.
 
Howvever I beleive it is more practical to mention flow of charge/electron as
it will demonstrate to the examiner that you are fully aware of what is occuring within a circuit.

An example to this is that once a wise physicist said it was technically incorrect
to say "the flow of CURRENT" (which most physics studebts do use today)as this genrally
translates to "the flow of FLOW OF CHARGE", which really doesn't make sense(dont worry though,
i believe you won't be penalised for this mistake, unless someone from VCAA sees this ).
What i am try to get at with this exmaple is that it is more possible to write more fluent and meaningful answers easily
when refering to flow charge as opposed to current.

If it helps what I usually do is needed mention "flow of charge"/"rate at which charge flows" first in an answer
and mention "current" in brackets, which then allows me to use "current" there after in the answer without having always
say "...rate at which charge flows..."(:p i am too lazy when it comes to writing and it save space!)

And when it comes to cathodes and anodes (electrodes) of a cell (i.e. battery) in short
cathode is the negtive side and anode is the positive side.
It is important to remember when talking about electrodes:
-CONVENTIONTIAL CURRENT is from anode to cathode(+ tp -)
-CHARGE/ELECTRONS flows from cathode to anode (- to +)

Hope this has cleared the confusion for you.

PS
that wise physicist I mentioned can be found here: http://amasci.com/elect/vwatt1.html
this is only one of his electricity articles and many more can be found here: http://amasci.com/ele-edu.html

Whilst his attempt at humour can be quite poor at times, He has REALLY good explanations. 
Nevertheless an excellent resource

[kyzoo]

And when it comes to cathodes and anodes (electrodes) of a cell (i.e. battery) in short
cathode is the negtive side and anode is the positive side.

It can be reversed in certain situations.

[rashmi_34]

And when it comes to cathodes and anodes (electrodes) of a cell (i.e. battery) in short
cathode is the negtive side and anode is the positive side.

It can be reversed in certain situations.

Yea, I heard that too...
But i don't think its on the study design (unless if i have missed it)
I have only come across it in an IB textbook, but not VCE.