Thermal Expansivity Vocabulary

Practice vocabulary flashcards covering linear, area, cubic, real, and apparent expansivities from the physics notes.

Linear Expansivity

The fractional increase in length of a piece of a substance per degree rise in temperature, defined as $\alpha = \frac{\Delta l}{l_1(\theta_2 - \theta_1)}$, with the S.I. unit of per Kelvin ($K^{-1}$).

Area Expansivity

Also known as superficial expansivity ($\beta$), it is the fractional increase in area of a piece of a substance per degree rise in temperature, defined as $\beta = \frac{\Delta A}{A_1 \Delta \theta}$.

Relationship Between Area and Linear Expansivity

The relationship where area expansivity ($\beta$) is equal to two times the linear expansivity ($\alpha$), expressed as $\beta = 2\alpha$.

Cubic Expansivity

Also known as volume expansivity ($\gamma$), it is the fractional increase in volume of a piece of a substance per degree rise in temperature, defined as $\gamma = \frac{\Delta V}{V_1 \Delta \theta}$.

Relationship Between Cubic and Linear Expansivity

The relationship where cubic expansivity ($\gamma$) is equal to three times the linear expansivity ($\alpha$), expressed as $\gamma = 3\alpha$.

Apparent Cubic Expansivity

The increase in volume per unit volume per degree rise in temperature of a liquid when the expansion of the vessel is not considered ($\gamma_a$).

Apparent Volume Expansivity (Mass Basis)

An expression for apparent cubic expansivity defined as $\gamma_a = \frac{\text{mass of liquid expelled}}{\text{Mass of liquid remaining} \times \text{rise in temperature}}$.

Real Cubic Expansivity

Also called absolute cubic expansivity ($\gamma_r$), it is the actual increase in volume per unit volume per degree rise in temperature when the expansion of the vessel is taken into consideration.

Relationship Between Real and Apparent Expansivity

The relation stating that the real cubic expansivity of a liquid equals its apparent cubic expansivity plus the cubic expansivity of its container, expressed as $\gamma_r = \gamma_a + \gamma$.