Question

thermal expansion in solids

Answer 1

Thermal expansion is the increase, or decrease, of the size (length, area, or volume) of a body due to a change in temperature. Thermal expansion is large for gases, and relatively small, but not negligible, for liquids andsolids.

Answer 2

Question:

thermal expansion in solids

Answer:

It has been observed that solids expand on heating and their expansion is nearly unitorm over a wide range of temperatulre.

Consider a metal rod of length Lo at certain temperature To. Let its length on heating to a temperature T becomes L. Thus,

Increase in length of rod = ΔL= L-Lo

Increase in temperature = ΔT = T-To

It is found that change in length ΔL of a solidis directly proportional to its original length and the change in temperature ΔT. That is;

$\implies\large \bf{ΔL∝L-L_o} \\ \implies\large \bf{ΔL=aL_oΔT} \\ \implies\large \bf{L-L_o=aL_oΔT} \\ \implies\large \bf{L=L_o(1+aΔT)}$

Where a is called the coefficient of linear thermal expansion of the substance.

$\green\implies\large \red\bf{ \bf \red{a = \frac{ΔL}{L_{o}ΔT} }}$

Thus,

We can define the coefficient of linear of linear expansion a of a substance as the fractional increase in its length per kelvin rise in temperature.