Mnemonics: Thermal Properties of Matter | Physics Class 11 - NEET PDF Download

1. Modes of Heat Transfer

Mnemonic: "Cool Cats Rest"

• Cool – Conduction

• Cats – Convection

• Rest– Radiation

Conduction: The process of heat transfer through direct contact between particles of a substance. It occurs in solids when particles vibrate and pass energy to neighboring particles.Example: A metal spoon getting hot when placed in a cup of hot tea.

Convection: Heat transfer through the movement of fluid (liquid or gas) particles. As a fluid heats up, it becomes less dense and rises, while cooler fluid sinks.Example: The warm air circulating inside a room from a heater.

Radiation: Heat transfer through electromagnetic waves (like infrared radiation), which does not require a medium.Example: Heat from the Sun reaching Earth through the vacuum of space.

2. Expansion of Solids

Mnemonic: "Little Ants Venture Everywhere"

• Little – Linear Expansion

• Ants – Areal Expansion

• Venture – Volume Expansion

• Everywhere – Expansion Coefficients (α, β, γ)

Linear Expansion: Refers to the change in length of an object when its temperature changes.
Formula: ΔL = αL₀ΔT, where α is the coefficient of linear expansion.

Areal Expansion: Refers to the change in the area of an object when its temperature changes.
Formula: ΔA = βA₀ΔT, where β is the coefficient of areal expansion.

Volume Expansion: Refers to the change in volume of an object when its temperature changes.
Formula: ΔV = γV₀ΔT, where γ is the coefficient of volume expansion.

Expansion Coefficients: These coefficients (α, β, and γ) represent how much the length, area, and volume of a material change per unit temperature change.

3. Newton’s Law of Cooling

Mnemonic: “Cool Rate Drops”

• Cool – Cooling

• Rate – Rate ∝ ΔT (temperature difference)

• Drops – Decreases over time

Newton's Law of Cooling suggests that the rate at which an object cools is proportional to the difference between its current temperature and the ambient temperature. The greater the difference, the faster the object cools. Over time, as the temperature of the object approaches the surrounding temperature, the cooling rate decreases.

4. Calorimetry Equation

Mnemonic: “Cold Equals Hot”

• Cold – mcΔT (cold object)

• Equals – Equals

• Hot – mcΔT (hot object)

This mnemonic represents the concept of heat exchange between two objects at different temperatures, typically used in calorimetry. When a hot object and a cold object are brought into contact, heat flows from the hotter object to the colder one until thermal equilibrium is reached.

The heat gained by the cold object equals the heat lost by the hot object, and can be expressed as:

m_cold c ΔT_cold = m_hot c ΔT_hot

Where:

• m = mass of the object

• c = specific heat capacity of the substance

• ΔT = change in temperature of the object

This equation reflects the principle of conservation of energy, as the total heat remains constant in an isolated system. The mnemonic helps in recalling this idea that the heat transferred to a cold object equals the heat lost by the hot object.