# What is the variation of ammeter reading with PQ

Honestly, this is a homework question. A screenshot of it is given below: Okay these are the things I have done in order to take the answer.

1. First I calculate the equivalent resistance which comes form 1000 ohms and 10 ohms.
2. Therefore I assume that total resistance of the circuit is increasing.
3. And since the potential difference is constant for the equivalent resistance, I get the relationship of current is indirectly proportional to resistance by using Ohm's law.

So according to my argument a graph should indicate a decrement of current with distance PQ, but here in the answer I don't have such a thing. So I think I have done something wrong, so that is why I'm asking this question here!

• If you move X upwards, I'd say the QX decreases (resistance is directly proportional to length).This will come in series with a parallel combo of XP and 10 ohm. Tip : You can find this equivalent resistance ( Qx + ( Px || 10) ) and differentiate it to check the slope. – Plutonium smuggler May 14 '15 at 10:43
• Your pathway seems a longcourse – On the way to success May 14 '15 at 11:05
• Its a path to sucess !! :P – Plutonium smuggler May 14 '15 at 11:06
• Try a couple of examples: What is the current when X=P? What is it when X=Q? What is it when X is halfway between P and Q? You'll eventually see a pattern that resembles one of the graphs. – Dave Tweed May 14 '15 at 11:17
• could you say the which path that the current will take when X=P – On the way to success May 14 '15 at 11:21