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Physics:on the move unit 4 june 2014 edexcel

http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/june2010-qp/6PH04_01_que_20100618.pdf

someone please help me with question 16? how does a capacitor provide constant voltage?

Reply 41

13142vp

Original post by shona_x.

http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/june2010-qp/6PH04_01_que_20100618.pdf

someone please help me with question 16? how does a capacitor provide constant voltage?

I got stuck on this question before
basically what i understood by my physics teacher is that capacitor charges up very quick but discharges very slowly(exponentially) so by the time voltage drops and rises capacitor discharges very little. so with little fluctuation it is kept about constant.
hope it helped :smile:

Reply 42

Bella_R95

4

Any predictions that might come up in this paper? I think there will be a big question on transformers they have hardly used that in past papers.

Reply 43

jtbteddy

5

Original post by Bella_R95

Any predictions that might come up in this paper? I think there will be a big question on transformers they have hardly used that in past papers.

Any notes on transformers?

Posted from TSR Mobile

Reply 44

Bella_R95

4

Original post by jtbteddy

Any notes on transformers?

Posted from TSR Mobile

® Transformers work by electromagnetic induction. An alternating current flowing in the primary coil produces a magnetic flux. The magnetic field is passed through the iron core to the secondary coil, where it induces an alternating voltage of the same frequency.
® Step up transformers increase voltage by having more secondary coils.
Step down transformers reduce the voltage by having fewer coils in the secondary coil

Reply 45

YA BISH

Has anyone got any useful revision notes on this unit ?

Reply 46

shona_x.

Original post by 13142vp

I got stuck on this question before
basically what i understood by my physics teacher is that capacitor charges up very quick but discharges very slowly(exponentially) so by the time voltage drops and rises capacitor discharges very little. so with little fluctuation it is kept about constant.
hope it helped :smile:

Thanks for this!! Helped a lot x

Reply 47

mar007

Original post by 13142vp

cool thanks
question 13 part (b)
see attached

Where did you get this paper and do you have unit 2 jan 2014 ?

Reply 48

13142vp

Original post by mar007

Where did you get this paper and do you have unit 2 jan 2014 ?

see attached i got the unit 5 one as well :smile:

(edited 9 years ago)

WPH02_01_msc_20140306.pdf184.8KB

WPH05_01_que_20140124.pdf814.8KB

WPH05_01_msc_20140306.pdf258.5KB

Reply 49

13142vp

Original post by mar007

Where did you get this paper and do you have unit 2 jan 2014 ?

uploading unit 2 question paper giving me problems

Reply 50

Freddy-Francis

9

Wohoo at last found the Unit 4 Thread :P

Reply 51

Jaydude

11

How are we all feeling? Prepared?

Posted from TSR Mobile

Reply 52

mar007

How to do UNIT 4-JAN 2013 paper question 15 c) ii) I know we are suppose to use a quarter instead of three quarter but I still can't get the answer.

Reply 53

JoshThomas

Guys an explanation to why b is the answer would be appreciated :tongue:

Not by process of elimination pleaee

(edited 9 years ago)

Reply 54

jtbteddy

5

Original post by mar007

How to do UNIT 4-JAN 2013 paper question 15 c) ii) I know we are suppose to use a quarter instead of three quarter but I still can't get the answer.

Well, youve got the value of the initial current and the voltage. V=IR, so use that to find R

Youve also got the value of the tine constant which = RC, so use that to find C

Reply 55

mar007

Why do you know the current or emf is induced ?

Reply 56

MO2898

7

Original post by JoshThomas

Guys an explanation to why b is the answer would be appreciated :tongue:

Not by process of elimination pleaee

Switch is opened

Magnetic field in right coil collapses

Left coil quickly reacts by producing a large EMF to compensate for the change

Reply 57

Nough

Original post by mar007

Why do you know the current or emf is induced ?

Simply put, when talking about magnets and coils, the magnetic flux induces an EMF. Always. Sometimes, if the resistance is low enough, this will mean a current, but not necessarily. So you always put EMF.

Reply 58

mar007

Original post by Nough

Simply put, when talking about magnets and coils, the magnetic flux induces an EMF. Always. Sometimes, if the resistance is low enough, this will mean a current, but not necessarily. So you always put EMF.