The relation between the coefficient of linear expansion (α) and the coefficient of area expansion (β) is:
beta = 2alpha
α (alpha) = coefficient of linear expansion
It tells how much the length of a material changes with temperature.
Thermal expansion is the tendency of matter to change its volume, area, or length in response to a change in temperature. As materials are heated, their molecules vibrate more and move apart, causing expansion; cooling causes contraction.
Key Aspects of Thermal Expansion
Types of Expansion:
1. Heat
Heat is a form of energy that transfers from one body to another due to a difference in temperature.
Heat always flows from a hot object to a cold object.
It is a form of energy.
The SI unit of heat is Joule (J).
It is measured using a calorimeter.
Modulus of Rigidity (Shear Modulus)
The modulus of rigidity is a physical quantity that measures the ability of a material to resist deformation when a shear force is applied.
In simple words, it tells us how difficult it is to change the shape of a material without changing its volume.
Definition:
The modulus of rigidity is defined as the ratio of shear stress to shear strain within the elastic limit of a material.
Modulus of Elasticity (Elastic Modulus) is a physical quantity that measures how much a material resists deformation (stretching or compressing) when a force is applied.
Modulus of elasticity is the ratio of stress to strain within the elastic limit of a material.
E = Stress/Strain
Strain is the deformation (change in shape or size) of a body when a force is applied. It tells us how much an object changes compared to its original size.
In simple words:
Strain = Change in dimension / Original dimension
So mathematically:
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