Chapter 14 - Energy Transfer by Heating

Question 1

What is conduction by energy caused by in a metal?

Answer 1

Free electrons transferring energy inside the metal

Question 2

Why are non-metals poor conductors?

Answer 2

Don’t contain free electrons

Question 3

What happens to the free electrons in conduction?

Answer 3

They gain KE and increase in speed. Then spread out and collide with other free electrons. Transfer free KE to other ions and electrons

Question 4

Why is there a smoother energy transfer in metals (conduction)

Answer 4

Electrons aren’t held inside atoms

Question 5

Define convection

Answer 5

Circulation of a fluid caused by heating it

Question 6

What happens to a liquid when you heat it?

Answer 6

Becomes less dense and rises

Question 7

Why do fluids rise when heated?

Answer 7

They expand, volume increases and density decreases

Question 8

Define evapouration

Answer 8

When a liquid turns into a gas

Question 9

Define condesation

Answer 9

When a gas turns into a liquid

Question 10

What causes a liquid to cool down?

Answer 10

Faster moving particles escaping the liquid

Question 11

How can you increase the rate of evaporation?

Answer 11

Increasing the SA, Temp or creating a draft of air over the liquid

Question 12

How can you increase the rate of condensation?

Answer 12

Increasing the SA or lowering the temp of the surface

Question 13

What is infrared radiation?

Answer 13

Energy transfer by EM waves

Question 14

Do all objects emit infrared radiation?

Answer 14

Yes

Question 15

What happens to the infrared radiation if you increase the objects temp?

Answer 15

The rate increases over time

Question 16

Do all objects absorb infrared radiation?

Answer 16

Yes

Question 17

What properties must an object have to emit more infrared radiation?

Answer 17

Dark, Matt

Question 18

What properties must an object have to emit less infrared radiation?

Answer 18

Light, shiny

Question 19

What properties must an object have to absorb more infrared radiation?

Answer 19

Dark, matt

Question 20

What properties must an object have absorb less infrared radiation?

Answer 20

Light, shiny

Question 21

What happens to radiation reflected from dark, matt surfaces?

Answer 21

Hit the surface again

Question 22

What happens to radiation reflected from light shiny surfaces?

Answer 22

Travels away from the surface

Question 23

What does the rate of energy transfer depend on?

Answer 23

Shape, size, material, nature of surface, temp difference

Question 24

How does a vacuum flask keep the temp of a drink inside it hot?

Answer 24

Cuts out a lot of conduction, convection, evaporation and radiation

Question 25

What cuts down conduction in a vacuum flask?

Answer 25

Vacuum between 2 walls, Glass is a poor conductor,

Question 26

What cuts down convection in a vacuum flask?

Answer 26

Vacuum between 2 walls,

Question 27

What cuts down evaporation in a vacuum flask?

Answer 27

Plastic cap

Question 28

What cuts down radiation in a vacuum flash?

Answer 28

Light, silvery surfaces

Question 29

What is true about the expansion of gases and solids and liquids?

Answer 29

Gases expand much more when heated

Question 30

Name an application of expansion of heating

Answer 30

Thermometers and thermostats containing liquid

Question 31

What do all buildings and bridges need to have?

Answer 31

Expansion gaps