Edexcel Physics Unit 2 "Physics at work" June 2013

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Also guys, latest confusion what is potential difference? I understand that it is the measure of energy transfer in between 2 points in an electric circuit or it drives the circuit by forcing the current to flow but still I feel a bit confused. Say if I calculate the potential difference and get 3V what does that actually mean?

3V means that 3J is work done on a coulomb (bunch of electrons) of charge when passing through a component.

Reply 141

B-Stacks

Original post by sarah.102

The 3V is the energy transferred from the source of energy, EMF. 3V from however much the cell provides to the circuit.

(edited 10 years ago)

Reply 142

JoshThomas

Original post by krisshP

3V means that 3J is work done on a coulomb (bunch of electrons) of charge when passing through a component.

Yaaa^^

Reply 143

JoshThomas

Original post by B-Stacks

The 3V is the energy transferred from the source of energy, EMF. 3V from however much the cell provides to the circuit.

Thats helped my understanding too, thanksss!

Reply 144

GCSE-help

Original post by sarah.102

A potential difference of 3Volts means 3 joules is given to every coloumb of charge, to push it around a circuit. Now if you used 10 volts, you'd give 10 joules to every coloumb, so the current would get a bigger 'push'. But it's important to remember PD is NOT a force, it's just a transfer of energy.

Reply 145

KBenzema

I dont understand part (b). On the mark scheme it says that after doing E=hf you have to divide Power(10W) by th energy found. why?

Reply 146

RankWinner

Original post by KBenzema

I dont understand part (b). On the mark scheme it says that after doing E=hf you have to divide Power(10W) by th energy found. why?

If you don't remember it it's also on the formula sheet, E = hf, the energy of a photon is equal to Plank's constant times its frequency. I've put the rest in spoiler tags, see if you understand it more before looking at the next hint.

Spoiler

(edited 10 years ago)

Reply 147

sarah.102

Can somebody please explain to me polarisation? It baffles me for some reason. Reading more and more into it has confused me.

Reply 148

Boy_wonder_95

Original post by sarah.102

Can somebody please explain to me polarisation? It baffles me for some reason. Reading more and more into it has confused me.

Spoiler

(edited 10 years ago)

Reply 149

justinawe

Original post by Boy_wonder_95

iirc Malus's law isn't in the Edexcel syllabus, but I could be wrong. May still be useful though :dontknow:

Reply 150

avipsita

Original post by justinawe

iirc Malus's law isn't in the Edexcel syllabus, but I could be wrong. May still be useful though :dontknow:

Who's law?? :confused:

Reply 151

krisshP

Original post by sarah.102

Can somebody please explain to me polarisation? It baffles me for some reason. Reading more and more into it has confused me.

read this
http://www.thestudentroom.co.uk/showthread.php?t=2308352&p=42866490

Reply 152

CharlieTT

I think I have discovered the angriest Physics lecturer ever.
[video="youtube;luXW6AFSloA"]http://www.youtube.com/watch?v=luXW6AFSloA&list=PLEEAF7F80E205E50E[/video]

Reply 153

KBenzema

i have a big doubt on part (a)(iii)
why do i get a different answer depending on the formula i use. im baffled.
P=IV : (0.75)*3=2.25w
P=I^2R : (0.75)^2*3.6 = 2.025w
P=V^2/R : (3)^2/3.6 = 2.5w

Reply 154

krisshP

Can somebody help me with section a question 7 on paper January 2012 unit 2 please? I don't get it at all

V=IR
I=V/R

There's constant pd so surely as R increases, I decreases linearly, giving B as the answer?

Thanks

Reply 155

krisshP

In January 2012 paper unit 2 q18a, they said core - cladding. Does this means that light travels from core into cladding, or light travels from cladding? HOW do you know?

Thanks

Reply 156