During a hot summer day, overhead power cables between two utility poles are observed to sag more than they do on a cold winter day. Why do the cables sag more in summer?
The cables expand due to the higher temperature in summer.
The cables contract due to the higher temperature in summer.
The utility poles move closer together when it is hot.
The air pressure is lower in summer, allowing the cables to hang lower.
96 exam-style questions on CIE IGCSE Physics 2.2.1 Thermal expansion of solids, liquids and gases. Each one has a worked solution and a mark scheme showing where the marks go.