Introduction:
The coefficient of linear expansion in solids is a measure of how much a solid expands when heated. It is denoted by α and is defined as the fractional change in length for a unit change in temperature.

Formula:
α = (ΔL / Lo) / ΔT

where ΔL is the change in length, Lo is the original length, and ΔT is the change in temperature.

Explanation:
When a solid is heated, its atoms and molecules vibrate more vigorously, leading to an increase in the distance between them. This results in an increase in the length of the solid. The coefficient of linear expansion quantifies this change.

Factors affecting α:
The coefficient of linear expansion is affected by several factors, including the type of solid, the temperature range, and the presence of impurities. For example, metals typically have higher coefficients of linear expansion than non-metals.

Applications:
The coefficient of linear expansion is used in several applications, including the design of bridges and buildings, the calibration of thermometers, and the manufacture of electronic devices.

Conclusion:
In conclusion, the coefficient of linear expansion in solids is an important property that measures how much a solid expands when heated. It is affected by several factors and is used in various applications.