Question

Sagging of telephone wires during summer is due to thermal expansion.

• A. True
• B. False

Answer 1

The correct option is A True

Thermal Expansion

1. The expansion produced in matter due to the absorption of heat energy and rise in temperature is called thermal expansion.
2. When a substance is heated, the kinetic energy of its molecules increases. Thus, the molecules begin vibrating or moving more and usually maintain a greater average separation.
3. The relative expansion divided by the change in temperature is called the material's coefficient of thermal expansion and generally varies with temperature.

The sagging of telephone wires during summer is;

1. Metals expand in heat and shrink in cold temperatures.
2. Electrical wires being made of metals become warmer due to rising temperature and expand in both length and diameter.
3. That is why they sag in summer.

Hence, the given statement is true.