Thermal Physics

Question 1

Define:
Brownian Motion

Answer 1

Brownian motion describes the random movement of microscopic particles suspended in a fluid, caused by collisions with the fast-moving molecules of the fluid.

This motion is characterized by erratic, zigzag paths due to continuous and random collisions from all directions.

Question 2

Define:
Thermal Expansion

Answer 2

• Solids exhibit the smallest expansion with temperature rise due to strong intermolecular forces and limited particle mobility.
• Liquids expand more than solids but less than gases, as they have moderate intermolecular forces and some particle mobility.
• Gases undergo the greatest expansion with temperature rise due to weak intermolecular forces and high particle mobility, allowing them to occupy a larger volume as their particles move farther apart.

Question 3

Define:
Specific Heat Capacity

Answer 3

• specific amount of heat energy required to raise temperature by 1 degree celsius for 1kg of substance
• An increase in temperature of an object corresponds to a rise in the average kinetic energies of all its particles.
• This increase in kinetic energy leads to faster and more intense particle motion, affecting the object’s physical properties such as expansion, phase changes, and pressure exertion in the case of gases.

Question 4

3 ways of heat transfers

Answer 4

1. Conduction
2. Convection
3. Radiation

Question 5

Define:
Radiation

Answer 5

• To maintain a constant temperature, an object must transfer energy away at the same rate it receives energy.
• If the rate of energy received exceeds the rate of energy transferred away, the object’s temperature will rise, and vice versa.
• The temperature of the Earth is influenced by the balance between incoming solar radiation and outgoing terrestrial radiation, with factors such as greenhouse gases affecting this balance and contributing to changes in the Earth’s temperature.

Question 6

Define:
Convection

Answer 6

Convection is the process of transferring heat through air or liquid currents. Convection causes liquid or gas to heat up, expand, and decrease in density

Question 7

Define:
Conduction

Answer 7

Conduction is when heat moves from one object to another object through direct touch.