What is the coefficient of linear expansion and how is it mathematically defined?

The coefficient of linear expansion is defined as the fractional increase in length per degree Celsius rise in temperature. It is mathematically given by, where Δℓ is the change in length, ℓ is the original length, and ΔT is the change in temperature.

Fill in the blanks: The thermal expansion of solids can be classified into ___, ___, and ___.

Linear expansion, superficial expansion, and cubical expansion

True or False: The coefficient of linear expansion is negative for all solids.

False. The coefficient of linear expansion is positive for most solids except for some materials like plastic, which have a negative coefficient.

What is latent heat, and how is it related to phase changes in substances?

Latent heat is the amount of heat required to change the state of a substance without changing its temperature, such as during melting or vaporization.

Riddle: I expand when the temperature rises, yet I do not have a shape. What am I?

A liquid

What is the relationship between the coefficient of linear expansion (α) and the coefficient of superficial expansion (β)?

The relationship is given by β = 2α, meaning that the coefficient of superficial expansion is twice that of linear expansion.

What does the term 'thermal conductivity' refer to?

Thermal conductivity is a material property that indicates how well a material can conduct heat, represented by the coefficient k in the heat conduction equation.

How does the time period of a pendulum clock change with temperature, and why?

The time period of a pendulum clock increases with temperature because the effective length of the pendulum increases as the material expands, causing it to swing more slowly.

True or False: The apparent expansion of a liquid accounts for the expansion of both the liquid and the container.

False. Apparent expansion only considers the expansion of the liquid, not the container.

What happens to the density of a solid when it is heated, and why?

When a solid is heated, its density typically decreases because its volume increases due to thermal expansion while its mass remains constant.

What is the formula for calculating the specific heat (s) of a substance?

The formula is Q = m × s ×Δθ, where Q is the heat supplied, m is the mass, and Δθ is the change in temperature.

How does the process of conduction work in solids?

In conduction, heat is transferred through molecular collisions without any movement of the molecules from their positions, primarily occurring in solids.

True or False: In forced convection, the movement of fluid is due to natural density differences.

False. In forced convection, the movement of fluid is caused by an external force, such as a fan or pump.

What is the relationship described by Stefan's Law of Radiation?

Stefan's Law states that the amount of energy radiated per unit area per second is directly proportional to the fourth power of the absolute temperature (E ∝ T⁴).

Fill in the blank: The amount of radiant energy emitted per second from a unit area of a radiating surface is called ___ power.

Emissive

What is the significance of Kirchhoff's Law of Radiation?

Kirchhoff's Law states that at a given temperature, the spectral emissive power of a body is directly proportional to its spectral absorbing power, indicating that good absorbers are also good emitters.

What happens to the energy distribution of black body radiation as the temperature increases?

As the temperature increases, the total energy emitted by a black body increases and shifts towards shorter wavelengths.

Fill in the blank: The process in which heat is transferred through electromagnetic waves is called ___.

Radiation

What is the specific heat of water, and why is it significant?

The specific heat of water is approximately 4.18 J/g°C, which is significant because it allows water to absorb a lot of heat without a large increase in temperature, stabilizing climates and biological systems.

If the length of a rod at 0°C is ℓ₀, what is its length at T°C given the coefficient of linear expansion α?

The length at T°C is given by ℓ = ℓ₀(1 + αT).