Heat Transfer

Question 1

Where does conduction mainly occur

Answer 1

Solids

Question 2

Where does Convection mostly occur

Answer 2

Liquids and Gases

Question 3

Where does Radiation mostly occur

Answer 3

Solids, Liquids and Gases

Question 4

What type of solid is Conduction faster in and why

Answer 4

Denser ones because they’re closer together so collide more

Question 5

What is conduction

Answer 5

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

Question 6

Why are metals good conductors

Answer 6

The have free electrons to move around inside the metal.

Question 7

What are the 3 types of heat energy transfer

Answer 7

Conduction
Convection
Radiation

Question 8

An object hotter than its surroundings emits…

Answer 8

More radiation than it absorbs

Question 9

An object cooler than its surroundings emits..

Answer 9

less radiation than it absorbs

Question 10

The hotter the object the (more/less) radiation it radiates over a given time

Answer 10

More

Question 11

What are Black/Dark/Matte surfaces good for?

Answer 11

Absorbing infrared radiation

Emitting more infrared radiation

Question 12

What are light/shiny surfaces good for?

Answer 12

Reflecting infrared radiation

Question 13

Why do solar panels use back painted pipes/ black surface

Answer 13

Because radiation from the sun is absorbed by the black surface to hear water in the pipes

Question 14

What is convection

Answer 14

When more energetic particles move from the hotter region to the colder region taking with them their heat energy

Question 15

What are convection currents about

Answer 15

Chances in density

Question 16

What containers is convection most efficient in and why

Answer 16

Roundish/Squarish

They allow the currents to work best

Question 17

Name 3 things the rate of hear transfer depends on

Answer 17

Volume
Types of Material
Size of surface area

Question 18

How does type of material affect the rate of heat transfer

Answer 18

Some are good conductors so transfer heat quicker

Question 19

How does size of SA affect rate of heat transfer

Answer 19

Bigger surface area = more infrared waves being emitted

Question 20

How does Volume affect rate of heat transfer

Answer 20

Smaller volumes will cool quicker because a higher proportion of object will be in touch with its surroundings

Question 21

Give 4 ways a vacuum flask is adapted to stop hear loss

Answer 21

• Insulating foam
• Double walled with vacuum between
• Silvered walls
• Plastic stopper

Question 22

How does silvered walls stop heat loss in a vacuum flask

Answer 22

Keeps heat loss by radiation at a minimum

Question 23

How does insulating foam affect heat loss in a vacuum flask

Answer 23

Minimises conduction to or from the outer glass bottle

Question 24

How does a double walled glass bottle affect heat loss in a vacuum flask

Answer 24

Stops conduction and convection through sides

Question 25

How does a plastic stopper affect heat loss in a vacuum flask

Answer 25

reduces heat conduction through it