A resistor is connected to a battery through a key as shown in words below. Point P is at the end of the resistor nearer to the positive terminal of the battery, and point Q is at the other end nearer to the negative terminal. Two further points R and S are on the connecting wires well away from the resistor.
(i) The potential difference across the resistor is to be measured after the key is closed. Between which two named points should a voltmeter be connected? Give reason.
(ii) Suppose by mistake the voltmeter is connected between points P and R instead. Predict the reading it would show and explain your answer.