IB Physics B.1 Thermal Energy Transfers Questionbank

Which of the following is a correct SI unit of specific heat capacity?

Two iron cubes $A$ and $B$ have side lengths $L$ and $2L$ respectively. When a temperature difference is placed across two opposite faces of cube $A$, the power transferred across the cube is $P$. When the same temperature difference is placed across two opposite faces of cube , what is the power transferred across the cube in terms of ?

A student compares the thermal conductivity of two rods made from different materials: copper (Rod A) and steel (Rod B). Each rod has the same length, diameter, and is heated at one end with an identical electric heater. The student places thermocouples at two fixed positions on each rod and measures the temperature at those points after 300 seconds. The results are shown in the table below.

A satellite component made of aluminum is exposed to sunlight in space and reaches thermal equilibrium. If the absorbed solar power is $1.3\ \mathrm{kW\ \mathrm{m^{-2}}}$ and the component has emissivity $e = 0.20$, what is its equilibrium temperature?

A microprocessor is attached to a metal heat sink to prevent overheating. Thermal energy is transferred at two interfaces:

• Interface 1: between the upper face of the microprocessor and the base of the heat sink, which are pressed together with a thin layer of solid thermal interface material between them.
• Interface 2: between the outer surfaces of the heat sink fins and the surrounding air, which flows freely past them.

Which row correctly identifies the primary mechanisms of thermal energy transfer at interface 1 and interface 2?