P1.1 The transfer of energy by heating processes and the factors that affect the rate at which the energy is transferred Flashcards Preview

Physics: P1 > P1.1 The transfer of energy by heating processes and the factors that affect the rate at which the energy is transferred > Flashcards

Flashcards in P1.1 The transfer of energy by heating processes and the factors that affect the rate at which the energy is transferred Deck (45)
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1
Q

How can heat be transferred?

A

Radiation, Conduction and Convection

2
Q

What is heat radiation?

A

The transfer of heat energy by infra-red radiation

3
Q

What do conduction and convection involve?

A

The transfer of energy by particles

4
Q

What is conduction the main form of heat transfer in?

A

Solids

5
Q

What is convection the main form of heat transfer in?

A

Liquids and Gases

6
Q

What can infrared radiation be emitted by?

A

Solids, Liquids and Gases

7
Q

What do all objects emit and absorb?

A

Infrared Radiation

8
Q

The bigger the temperature difference…

A

The faster the energy is transferred by heating

9
Q

Where is infrared emitted from?

A

The surface of an object

10
Q

The hotter an object is…

A

The more infrared radiation it radiates in a given time

11
Q

An object hotter than its surroundings…

A

Emits more radiation than it absorbs

12
Q

An object cooler than its surroundings…

A

Absorbs more radiation than it emits

13
Q

Which surfaces absorb and emit infrared radiation the best?

A

Dark, matt surfaces

14
Q

Which surfaces are poor absorbers and emitters of infrared radiation?

A

Light, shiny surfaces

15
Q

What do light, shiny surfaces do to infrared radiation?

A

They reflect it

16
Q

What forces hold a solid together?

A

Strong forces of attraction

17
Q

What arrangement does a solid have?

A

Regular and fixed

18
Q

How much energy do particles in a solid have?

A

Not much

19
Q

How do the particles in a solid move?

A

They vibrate around fixed positions

20
Q

What forces hold a liquid together?

A

Weaker forces of attraction

21
Q

What arrangement do the particles have in a liquid?

A

An irregular arrangement, the particles are close together but can move past each other

22
Q

How much energy do particles in a liquid have?

A

More energy than particles in a solid

23
Q

How do the particles in a liquid move?

A

In random directions at low speeds

24
Q

What forces hold a gas together?

A

Almost no forces of attraction

25
Q

What arrangement do the particles in a gas have?

A

None

26
Q

How much energy do particles in a gas have?

A

More energy than liquids and solids

27
Q

How do the particles in a gas move?

A

In random directions at high speeds, colliding into each other

28
Q

What happens when you heat a substance?

A

You give the particles more kinetic energy

29
Q

What is the process of conduction?

A

Where vibrating particles pass on their extra kinetic energy to neighbouring particles

30
Q

Why is conduction faster in solids?

A

Because the particles are closer together and therefore will collide more often and pass energy between them

31
Q

Why are metals good conductors?

A

Because of their free electrons which move through the metal colliding with particles and transferring energy

32
Q

When does convection occur?

A

When an area gets hotter its particles move further apart, this makes that area less dense and lighter than its surroundings so it rises. When it starts to cool the particles move closer together and it falls

33
Q

What is condensation?

A

When a gas cools turns into a liquid due to the particles losing kinetic energy

34
Q

What is evaporation?

A

When particles in a liquid with the most kinetic energy overcome the forces of attraction and escape turning the liquid into a gas

35
Q

What affects the rate of evaporation?

A

Temperature (faster if higher)
Density (faster if lower)
Surface Area (faster if larger)
Airflow (faster if greater)

36
Q

What affects the rate of condensation?

A

Temperature (faster if lower)
Temperature of the surface that the gas touches (faster if lower)
Density (faster if higher)
Airflow (faster if less)

37
Q

The bigger the surface area…

A

The more infrared waves that can be emitted/absorbed by the surface, so the quicker the transfer of heat

38
Q

The smaller the volume…

A

The quicker the object will cool

39
Q

What other factors affect the rate of heat transfer?

A

The type of material, the nature of the surface with which the object is in contact

40
Q

The bigger the temperature difference between an object and its surroundings…

A

The faster the rate at which the energy is transferred by heating

41
Q

What is the U-Value?

A

the rating to determine how good an insulator something is. The lower the u-value the better it is at insulating

42
Q

What is Payback time?

A

The amount of time it takes to save back on your energy bills the money spent on the insulation

43
Q

How do solar panels work?

A

They contain water that is heated by radiation form the sun

44
Q

What is specific heat capacity?

A

The amount of energy needed to raise the the temperature of a 1kg substance by 2 degree

45
Q

What is the word equation for specific heat capacity?

A

Energy = Mass x specific heat capacity x temperature range