GCE (A level) Physics E04 Emf and voltage. Part 2 of 2

[amirsthebest12]

thank you

[flightsnhike226]

In the first part to this you described the e.m.f as being the energy produced over the charge, but in this video you start off by saying it is the energy transferred over charge?

[Steve4Physics]

To sciencerocks1995

You could say total energy/total charge, or energy per unit charge (i.e. energy per coulomb). It amounts to the same thing.

[sciencerocks1995]

Wait, at 0:35 shouldn't the emf be total energy produced over charge ? Just asking ....

[TheMrLyons]

Like how the two videos are very idiot proof :) I personally understand the concepts but just needed to refresh my memory a little about the exact definitions, these videos are helping, Thanks for uploading :D

[shield543]

Don't retire, come to my school and teach physics :)

[Steve4Physics]

Hi Zuja59. Take a look at at my lessons on standard form (as it's called in the UK). They will show you what you need to know. Just search my channel (Steve4Physics) for 'Standard Form'. I would put the link here, but it appears that comments can't contain urls.

[Steve4Physics]

Not sure I fully understand but.....

The voltmeter 'can't tell' the difference between the effect of an emf from a source

and the effect of a potential difference across a resistor. This is because in both cases the overall effect is to push an extremely tiny current through the voltmeter.

[If you connect both leads of a voltmeter to the SAME terminal of a source

(e.g the positive terminal) then the reading is always zero because there's

nothing trying to push charges through the voltmeter.]

[zuja59]

I have a question, how did you calculate the

V=200kV

w=?

w=1.6x10 on the minus 19 x 200kV

w=....

I do understand the formula, but i do not understand that standard form thingy.

I did it like this on my calculator, 1.6x 0.0000000000000000001, then the number x 200, 000V.

So please if you could spare few words on this, thank you.

[hydragon]

I have a question: i can understand how the voltmeter measures voltage by taking the difference between one point and another (hence why the voltmeter displays zero on just the segment of wire), but then why wouldn't it display zero when connected to the source? unless the +'ve side has a value while the -'ve is zero... (still a newb lol)

[ColorsMelody]

Thank You~