Heat Radiation

Question 1

what are the three ways in which heat is transferred?

Answer 1

Radiation, Convection and Conduction

Question 2

what is infrared radiation?

Answer 2

Infrared radiation can be emitted in solids, liquids and gases, it is emitted from the surface of an object but the heat of object limits how much radiation is emitted. If an object is hot is will release much more radiation than it absorbs whereas if an object is cooler it will absorb more radiation than it emits

Question 3

what is convection?

Answer 3

Convection occurs when the more energetic particles move from the hotter region to the cooler region and take their energy with them (convection relies on density low density –> high density) and occurs in liquids and gases

Question 4

what is conduction?

Answer 4

Conduction of heat energy is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles and occurs in solids

Question 5

what is a solid?

Answer 5

Solids are particles held closely together in a fixed regular arrangement by strong forces of attraction. These particles don’t have much energy so can only move about in their fixed position

Question 6

what is a liquid?

Answer 6

Liquids are particles that are held closely together in irregular arrangements but can move past each other due to weaker forces of attraction. They have more energy and they move in random direction at a low speed

Question 7

what are gases?

Answer 7

Gases are particles that have almost no force of attraction and are free to move. These particles have a very high energy and therefore move at high speeds in random directions

Question 8

what is condensation?

Answer 8

Condensation is when a gas cools and the particles in the gas slow down and lose kinetic energy which then causes the attractive forces to pull them closer together. When the gas gets cool enough and the particles close together the gas becomes a liquid

Question 9

what is evaporation?

Answer 9

Evaporation is when particles escape from a liquid, this can happen at temperatures that are much lower than the liquids boiling point. Particles can only evaporate off the top of the surface if they are travelling in the right direction and at a fast enough speed to overcome the attractive forces of the other particles

Question 10

name the four ways that the rate of evaporation and condensation is affected

Answer 10

1. Temperature
2. Density
3. Surface Area
4. Airflow