Sec 3 Combined Science (Physics) Thermal Processes topical questions

State the direction of spontaneous thermal energy transfer between two objects at different temperatures, and state when the transfer stops.

Name the process of thermal energy transfer that needs no medium, and state how the Sun’s energy reaches Earth.

Explain why the base of a saucepan is made of metal.

Liquids and gases are poor conductors but transfer energy well by convection. Explain why.

Explain, in terms of density, how a convection current forms in a room heated by a floor-standing heater.

On a winter morning a metal railing and a wooden bench are both at 5 °C. Explain why the railing feels much colder to the touch.

A vacuum flask has (a) a vacuum between double walls, (b) silvered walls, (c) a plastic stopper. State the transfer process each feature limits and why.

At night, coastal areas often experience a land breeze blowing from the land towards the sea. Explain why, using convection.

Two identical metal cans hold equal volumes of water at 80 °C: one painted dull black, one shiny white, both standing in the same room with thermometers fitted. (a) Predict which cools faster and explain why. (b) State two controls that make the comparison fair. (c) The dull black can is refilled with ice-water: state what happens to its temperature compared with the shiny can, and why.

Water boils in a metal pan on a gas flame. Name and explain the transfer process that moves energy (a) through the pan’s base, (b) from the bottom of the water to the top, (c) from the pan to your face when you stand near it.

A house in a hot country has white shiny walls, a reflective roof coating, and thick foam insulation in the wall cavities. Explain how each feature reduces the rate at which thermal energy enters the house from outside.

For each of conduction, convection and radiation, state the medium required and give one everyday example with a one-sentence explanation of the mechanism.