IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: holtadit on December 08, 2009, 02:33:28 pm

Title: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 02:33:28 pm
Look at question 9 (c) of the attached paper.

How do they get I^2 R and what formula are they referring to. ?
Title: Re: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 03:32:08 pm
HELP!
Title: Re: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 03:35:31 pm
Also question 9 c ii of the attached paper .

THIS A DIFFERENT QUESTION FROM THE ONE ABOVE

How do u know in which way the flexible wire moves ? I applied flemings left hand rule but i dont know in which way the index finger points... where is the North and South poles ?
Title: Re: IGCSE physics easy question
Post by: astarmathsandphysics on December 08, 2009, 03:36:36 pm
Half am hour
Title: Re: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 03:41:35 pm
finally someone decides to help  :)
Title: Re: IGCSE physics easy question
Post by: astarmathsandphysics on December 08, 2009, 03:58:12 pm
The attacjed file is corrupt. I looked up the question on my version of the paper and it doesnt look the same as yours.
Title: Re: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 04:06:05 pm
For my first question see paper 3 may june 2008

for the second question see paper 3 november 2008
Title: Re: IGCSE physics easy question
Post by: astarmathsandphysics on December 08, 2009, 04:16:00 pm
P=IV but Y=IR so P=I(IR)=I^2R
Title: Re: IGCSE physics easy question
Post by: astarmathsandphysics on December 08, 2009, 04:19:26 pm
Use the right hand grip tule on the thick wire to find the direction of the field - clockwise and left hand rule on thin wire to find direction of force - towards thick wire. Alternativley you could just use - like currents attract.
Title: Re: IGCSE physics easy question
Post by: holtadit on December 08, 2009, 04:31:57 pm
for the left hand rule where would the index finger (magnetic field) point ? and why ?
Title: Re: IGCSE physics easy question
Post by: Ghost Of Highbury on December 08, 2009, 04:47:10 pm
lemme explain it to u ..hold on
Title: Re: IGCSE physics easy question
Post by: Ghost Of Highbury on December 08, 2009, 04:51:01 pm
i know the diagram sucks, but try to understand plz..

the middle finger shud point downwards, and the index finger shud point straight...hope u get it.

if not tell me..
Title: Re: IGCSE physics easy question
Post by: astarmathsandphysics on December 08, 2009, 05:18:49 pm
Wxactly right