CBSE Class 11-science Answered

Dear student,

The expansion in length is called linear expansion. The expansion in area is called area expansion. The expansion in volume is called volume expansion.

Linear expansion - l/l  a₁ T

Area expansion - A/A  2 a₁ T

Volume expansion -  V/V  3 a₁ T

The coefficient of linear expansion is denoted by the letter 'a' .

Where l = original length

The coefficient of linear expansion is a characteristic property of the material of the rod.

Expansion in area of a Laminar surface due to heating is known as superficial expansion.

Let a₁ = area of a surface

t₁ = its initial temperature

a₂ = area of the surface after heating

t₂ = final temperature

The coefficient of superficial expansion is defined as the ratio of increase in area to its original area for every degree increase in temperature.

Increase in area = a₂-a₁

Rise in temperature = (t₂-t₁)

Coefficient of superficial expansion (b)

.

Increase in volume of a solid on heating is cubical expansion.

Let V₁ = Initial volume at t₁⁰C

V₂ = its volume at t₂⁰C (t₂>t₁)

Then increase in volume 'v' = v₂-v₁

Increase in temperature 't' = t₂-t₁

The coefficient of cubical expansion is defined as the ratio of the increase in volume to its original volume for every degree increase in temperature. It is denoted by 'g'.

We can show that g = 3a

.

Regards

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