Physics (AS & A Level) · Oct / Nov 2024 · Paper 11 · Question 23

A wire consists of a 3.0 m length of metal X joined to a 1.0 m length of metal Y. The cross-sectional area of the wire is uniform. A load hung from the wire causes metal X to extend by 1.5 mm and metal Y to extend by 1.0 mm. The same load is then hung from a second wire of the same cross-sectional area, consisting of a 1.0 m length of metal X and a 3.0 m length of metal Y. Both wires are extended within their limit of proportionality. What is the total extension of this second wire?

1. A2.5 mm
2. B3.5 mm
3. C4.8 mm
4. D5.0 mm

As printed in the paper