# Ammeter readings of variable resistor

## Question

The diagram in question has no numerical values.

1. $$R_1$$ is a resistor of constant resistance. $$R_2$$ is a variable resistor set to minimal resistance.
2. $$V$$ is an ideal voltmeter. $$A_1$$ & $$A_2$$ are ideal ammeters following each equivalent resistor.
3. emf $$\varepsilon$$ has internal resistance $$r$$.

The variable resistor is being set to maximum resistance. Which of the following is true?

1. Ammeter $$A_1$$ would read lower current than before, Ammeter $$A_2$$ would read higher current than before.
2. Ammeter $$A_2$$ would read lower current than before, Ammeter $$A_1$$ would read higher current than before.
3. The voltmeter would read lower voltage.
4. Both Ammeters $$A_1$$ and $$A_2$$ would read lower current than before.

I was given this question and I suspect, after using made-up numerical values for each component, that the answers are incorrect, question is not phrased well, or rather the question is missing details.
Generally speaking, before delving into each answer, as long as the resistance of $$R_2$$ increases, the current in the circuit decreases, whilst the voltage of the circuit increases.
What I think of each answer is:

1. The current in the circuit decreases, while the resistance of $$R_2$$ increases, so less current would go through $$A_2$$ than originally. Can't be.
2. Not sure if its always true, but I found that it's true when the minimal and maximal resistance of $$R_2$$ is greater than that of $$R_1$$. But not if the min/max of $$R_2$$ is lower than that of $$R_1$$. So it can't be.
3. The voltage of the circuit increases when the current decreases. Can't be.
4. Since answer 2 is true in some cases, this can't be true.

Am I missing something?

Hint: It appears you are missing the effect of the voltage drop across the battery internal resistance $$r$$ when resistor $$R_2$$ is varied.