Physics (AS & A Level) · Feb / March 2023 · Paper 12 · Question 33

The table shows the properties of two different wires, P and Q. | | length | resistance | resistivity of material | |---|---|---|---| | wire P | $l$ | $R$ | $\rho$ | | wire Q | $2l$ | $\frac{1}{4}R$ | $\frac{1}{3}\rho$ | Wire P has a cross-section of diameter $d$. What is the diameter of the cross-section of wire Q?

1. A0.41$d$
2. B1.6$d$
3. C2.7$d$
4. D7.1$d$

As printed in the paper