20 Physics -- Thermal Expansion

Does any substance have a negative value of linear expansivity? Justify.

1 Answers

Yes, some substances have a negative value of linear expansivity, which means that they contract rather than expand when the temperature increases. This is because the expansion or contraction of a substance as a result of a change in temperature is determined by the behavior of the molecules that make up the substance.

The expansion or contraction of a substance is related to the kinetic energy of its molecules. When the temperature of a substance increases, the kinetic energy of its molecules also increases. As a result, the molecules are more likely to escape the attraction of their neighbors and move farther apart from each other, causing the substance to expand.

However, not all substances expand when the temperature increases. Some substances, such as certain types of metal alloys such as lead, have a negative value of linear expansivity, which means that they contract when the temperature increases. This is because the attractive forces between the molecules in these substances are strong enough to overcome the increase in kinetic energy caused by the increase in temperature. As a result, the molecules are more likely to move closer together rather than farther apart, causing the substance to contract.

Why does the cycle tube burst sometimes in summer?

In summeras the temperature increase , the pressure increases inside the tube This pressure would be enough to cross the breaking point of tyre making it to burst

Bodies in real life are three-dimensional. Why do we have linear expansion and superficial expansion when all the bodies should have had cubical expansion? Present your thoughts.

Why cannot we measure the cubical expansion of liquids directly?

Liquids do not have a definite shape nor a definite volume. In addition to this, direction application of heat in liquids is not practical. (Imagine putting water over the source of heat to heat it - either the source distinguishes or water evaporates). Thus, cubical expansion of liquid cannot be measured directly. It is measured by placing it in a vessel than applying related mathematical calculations.

Why does the level of liquid in a vessel initially fall and then rise again on heating?

Liquid is heated by keeping it in a container. When heat is supplied, all the supplied heat is absorbed by the container initially to increase its dimensions. Due to this, the volume of the container increases but that of the liquid remaining the same, the level of liquid in the container falls.

When the container has expanded enough and cannot take more heat, it then allows the liquid to consume the supplied heat. As the coefficient of cubical expansion of liquid is much greater than solid,...

Define linear expansivity, superficial expansivity and cubical expnasivity.

Linear expansivity, superficial expansivity, and cubical expansivity are three measures of how much an object expands as a result of a change in temperature. These measures are related to the behavior of matter at the molecular level.

Linear expansivity is a measure of how much an object expands in one dimension, such as its length, width, or height, as a result of a change in temperature. It is usually expressed in units of length per length per degree Celsius (e.g. meters per meter per...

Is there any substance with negative value of cubical expansivity? If so, present an example to strengthen your

It is theoretically possible for a substance to have a negative value of cubical expansivity, which means that the substance would contract rather than expand when the temperature increases. However, it is very rare for a substance to have a negative value of cubical expansivity over a significant range of temperatures.

One example of a substance that has a negative value of cubical expansivity over a limited range of temperatures is water. Water has a positive value of cubical expansivity at...

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