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)

 

[Nickie]

First of all, it's great that you're revising your circuit modules! Understanding parallel circuits can be tricky, but let's break it down. In a parallel circuit, the potential difference (PD) is the same for all components connected in parallel. This is because each component has its own individual path for the current to flow through.

Think of it like a highway with multiple exits. Each exit is like a component in a parallel circuit, and the highway is the battery. No matter which exit you take, you're still on the same highway and will experience the same speed and conditions. Similarly, in a parallel circuit, the electrons flow through each component at the same potential difference, just like the cars on the highway all experience the same conditions.

So in the diagram you provided, the PD across each resistor will be the same as the PD of the battery. This is because the battery is the source of the potential difference, and it is being divided among the parallel branches. The total PD across the parallel circuit will be equal to the PD of the battery.

Hope this helps clarify things for you. Keep up the good work with your revision!