Thermal Physics & Gas Laws – Vocabulary Review

Vocabulary flashcards covering gas laws, kinetic theory, heat transfer, and specific heat capacity concepts from the lecture transcript.

Absolute Zero

The lowest possible temperature (0 K or −273 °C) at which particles have minimum kinetic energy.

Kelvin Scale

An absolute temperature scale starting at absolute zero; 0 K corresponds to −273 °C.

Boyle’s Law

For a fixed mass of gas at constant temperature, pressure is inversely proportional to volume (p₁V₁ = p₂V₂).

Pressure–Temperature Law (Gay-Lussac’s Law)

For a fixed mass of gas at constant volume, pressure is directly proportional to absolute temperature (p/T = constant).

Kinetic Theory of Gases

Explains gas pressure as the result of molecules colliding with container walls; higher temperature means faster collisions and greater pressure.

Pascal (Pa)

SI unit of pressure equal to one newton per square metre; 1 kPa = 1 000 Pa.

Specific Heat Capacity (c)

Energy required to raise the temperature of 1 kg of a substance by 1 °C (or 1 K).

Thermal (Heat) Capacity

Total energy needed to raise an object’s temperature by 1 °C; equals mass × specific heat capacity.

Conduction

Transfer of thermal energy through a substance without bulk movement, via lattice vibrations and (in metals) free electrons.

Lattice Vibrations

Oscillations of atoms about fixed positions in a solid’s lattice; main mechanism of heat transfer in non-metals.

Free (Delocalised) Electrons

Mobile electrons in a metal that collide with atoms and rapidly transfer energy, making metals good thermal conductors.

Convection

Heat transfer in fluids caused by movement of warmer, less dense regions rising and cooler, denser regions sinking.

Thermal Radiation

Transfer of energy by electromagnetic waves; a shiny surface reduces radiation heat loss.

Efficiency

Useful output energy divided by total input energy, usually expressed as a percentage.

Watt (W)

SI unit of power equal to one joule per second.

Joule (J)

SI unit of energy or work.

Power

Rate at which energy is transferred or converted; calculated as energy ÷ time (P = E/t).

Useful Energy

Portion of input energy converted into the desired form (e.g., light from a lamp).

Waste Energy

Input energy not usefully transferred, often dissipated as heat or sound.

Specific Heat Capacity Experiment

Determines c by supplying electrical energy (E = Pt) to a known mass and measuring the temperature rise.

Thermal Expansion

Increase in size when heated; gases expand the most, solids the least.

Volume–Pressure Relationship

At constant temperature, doubling a gas’s volume halves its pressure, illustrating Boyle’s Law.