Heat Part 2 Quiz

Water has maximum density at 4°C, so its volume increases (density decreases) when cooled from 4°C to 0°C or heated above 4°C, unlike most substances that contract on cooling.

The metal with higher coefficient of linear expansion elongates more, causing the strip to bend toward the side with lower expansion coefficient.

Heat supplied is latent heat of vaporization (2260kJ/kg for water), used to overcome intermolecular forces, keeping temperature constant until phase change completes.

Specific heat capacity c = Q/(m ΔT); high c for water (4180 J/kg·K) means more heat energy is needed to increase its temperature compared to other substances.

In an isolated system, heat lost by hot body equals heat gained by cold body, assuming no loss to surroundings.

Thermal conductivity k measures rate of heat flow; metals like copper/silver have high k, allowing rapid conduction.

Heat passes through direct molecular collisions without net movement of material, primarily in solids.

Heating decreases density, causing warmer fluid to rise and cooler denser fluid to sink, setting up circulation.

Radiation involves electromagnetic waves (infrared for thermal), needing no material medium explains, heat from Sun reaching Earth.

It absorbs all incident radiation and emits maximally at given temperature, serving as ideal standard for radiation laws.