Question

Why are the telephone wires kept slightly loose, when they are laid in summer?

Answer 1

1. The most common change caused by heat is expansion. Matter increases in volume when there is an increase in temperature.
2. Expansion of Solids: A solid substance expands slightly on heating.
3. This expansion can be seen clearly as the change in shape and size of à solid are easily visible.
4. Telephone wires are made from metals so, metallic wires sag in summers due to intense heat of the sun.

Hence, the telephone wires kept slightly loose due to thermal expansion.