PHYSICS [1 Mark Question Answer]

Three different types of thermal expansion are linear expansion, superficial expansion and cubical expansion.

Expansion in area of a solid on heating is called superficial expansion.

Expansion in volume of solid, liquid or gas on heating is called cubical expansion.

The increase in length of a solid on heating is called linear expansion.

The expansion produced in matter due to the absorption of heat energy is called thermal expansion.

The process by which a liquid changes into its gaseous state at some fixed temperature by absorption of heat energy is known as boiling.

The change of a substance from its liquid state to its gaseous state at any temperature below its boiling point is called evaporation.

Liquids and gases have no linear or superficial expansion as they have no definite shape.

Electric transmission lines are always kept sagging between the electric poles to prevent them from snapping in winter due to contraction.

In winters, the air inside the tyres contracts and gets compressed. Hence, the tyres of a car filled with compressed air becomes slightly flat in winters.

In a saucer, larger area of tea is exposed. So, evaporation takes place from a larger area than in a cup. Hence, tea cools more rapidly in a saucer than in a cup.

A tightly fixed lid of a bottle when kept under hot water expands and gets loosened. So, it can be opened easily.