Enter the values shown for $V_X$ on the voltmeter and $I_S$ on the ammeter.
A resistor’s resistance is found from $\text{resistance} = \frac{\text{voltage across the resistor}}{\text{current in the resistor}}$. Work out $R_X$, the resistance of resistor X.
Explain why the switch is opened after the potential difference and current readings have been taken.
The potential difference $V_Y$ across Y is found from $V_Y = 3.0 - V_X$. Use this relation and your value of $V_X$ from (a)(i) to work out $V_Y$. Calculate the resistance $R_Y$ of Y.
Complete the circuit diagram in Fig. 2.3 so that the two resistors are shown in parallel between points W and Z. Draw the voltmeter connected to measure the potential difference $V_P$ across both resistors.
In theory, the total resistance $R_T$ is given by $R_T = \frac{R_X R_Y}{R_X + R_Y}$. Use this relationship together with your values of $R_X$ and $R_Y$ to find $R_T$.
The manufacturer states that the combined resistance of resistors X and Y when they are connected in parallel is $2.5\,\Omega$. State whether your value of $R_T$ found in (b)(ii) is the same as the manufacturer’s value. Justify your answer with a calculation. Two quantities may be taken as equal within experimental accuracy if their values differ by no more than $10\%$.