Thermal expansion of solids are:
3 types
Understanding Thermal Expansion in Solids
Thermal expansion is the tendency of matter to change in volume, area, and length in response to a change in temperature. When a substance is heated, its particles start moving more vigorously and spread out, causing the substance to expand. When it is cooled, the particles slow down and move closer together, causing the substance to contract.
Solids exhibit thermal expansion in a well-defined manner. Because solids have a fixed shape and volume at a given temperature, the expansion can be observed along different dimensions.
Types of Thermal Expansion in Solids
In the case of solid materials, thermal expansion is generally categorized into three main types based on the dimension along which the expansion is considered:
- Linear Expansion
- Superficial (Area) Expansion
- Volume (Cubical) Expansion
Linear Expansion
Linear expansion is the change in length of a solid when its temperature changes. This type of expansion is most significant when considering one-dimensional objects like rods or wires. The change in length is proportional to the original length and the change in temperature.
Superficial (Area) Expansion
Superficial expansion, also known as area expansion, is the change in the surface area of a solid when its temperature changes. This applies to two-dimensional objects like sheets or plates. The change in area is proportional to the original area and the change in temperature.
Volume (Cubical) Expansion
Volume expansion, or cubical expansion, is the change in the volume of a solid when its temperature changes. This is the most general type of thermal expansion, as all solids have volume. The change in volume is proportional to the original volume and the change in temperature.
Thus, there are primarily 3 types of thermal expansion observed in solids.
Important Questions from Thermal expansion
A copper rod and a steel rod are to have lengths LC and LS, such that the difference between their lengths is the same at all ambient temperatures. If the coefficients of linear expansion of copper and steels are αC and αS respectively. The lengths are related to the coefficient of linear expansion as :
How much should the temperature of a brass rod be increased so as to increase its length by 1%?
Given: for brass α = 0.00002/°CA wooden wagon wheel has an outside diameter of 3750 mm. The iron tire for this wheel is deliberately made smaller so that it can be shrunk in place to be a tight fit. If the tire's inside diameter is 3737 mm at 20°C, the temperature to which it must be heated to fit over the wheel? The coefficient of linear expansion of the steel is 1.2 × 10-5/°C.
A cylinder of cross-sectional radius 1 cm and height 4 cm is heated from 0°C to 100°C. If the coefficient of linear expansion α = 4 × 10-4/°C, what will be the increase in the volume of the cylinder?
Greater the value of _______ of a material, the more rapidly it will conduct heat.
