Potential difference in parallel circuit

[Johnahh]

Homework Statement

I am currently revising some AS level Circuit modules and I'm having trouble seeing how the P.D across 3 components in a parallel circuit can each have the same value as the P.D of the battery.
I am probably just being dumb but its just not making sense!
such as this:
http://physicsnet.co.uk/wp-content/u...l-circuits.jpg

 

[Sunil Simha]

I'm unable to access your problem. The link, when clicked, leads to a page which says Error 404:Page not found.

 

[Johnahh]

http://physicsnet.co.uk/a-level-physics-as-a2/current-electricity/circuits/ - right at the bottom
basically if you have a 12v supply with 3 components how can the PD across each component be 12 when 3x12 = 36v?

 

[Sunil Simha]

http://physicsnet.co.uk/a-level-physics-as-a2/current-electricity/circuits/ - right at the bottom
basically if you have a 12v supply with 3 components how can the PD across each component be 12 when 3x12 = 36v?

I'm sure you know that potential difference across an ideal conducting wire is always zero right?(Because no work is needed to be done by the electric field to move charges across it)

Now check out the attachment. (in the first figure) ABCD is an ideal conductor and so is PQRS. So potential difference across AB, BC and CD is zero right? Similarly across PQ, QR, RS.

So whatever was the potential at A will be the potential at B, C and D. Similarly, whatever was the potential at P will be the potential at Q, R and S.

Thus the potential difference across AP, BQ, CR and DS should be the same right?

So you can simply do away with all those excess connections and simply connect all the resistors across AP right? (Like in the second figure)

(In your question, when you added the voltages, you are siply adding thevoltages across the same two points)