Heat Energy Transfer Flashcards Preview

AQA Science P1,B1,C1 > Heat Energy Transfer > Flashcards

Flashcards in Heat Energy Transfer Deck (11)
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1
Q

What materials are good at absorbing Infrared Radiation?

A

Dark, Matt surfaces

2
Q

What surfaces are poor emitters of Infrared radiation?

A

Light, Shiny surfaces

3
Q

How do radiators primarily transfer thermal energy to a room?

A

Through Convection.

(Even though they are called radiators…)

4
Q

Why would a wooden block feel warmer than a metal block when they are both at the same temperature?

A

Metals are better conductors.

5
Q

What factors affect the rate at which an object transfers thermal energy?

A
  • The surface area
  • The material of the object
  • What the object is in contact with
6
Q

The lower the U-Value the…

A

better the material is as an insulator.

7
Q

Why do a vacuum flasks have a vacuum?

A

To stop heat lose through conduction and convection (but not IR).

8
Q

The silver metal object is a heat sink for a computer. It is fitted to help keep the computers components at a low temperature.

  • Why does it have ‘fins’?
  • Why is it made from a metal?
A
  • So that it has a large surface area (to increase heat transfer)
  • Metals are good conductors
9
Q

Why are metals good conductors of thermal energy?

A

They have free (delocalised) electrons.

10
Q

Explain how can all the air in a fridge be cooled if the unit only cools air at the top of the fridge.

A
  • When the air at the top is cooled down it become more dense.
  • The cool air sinks, allowing the wamer air to rise
  • The warm air is then cooled
  • This allows all the air in the fridge to be cooled
11
Q

How is thermal energy transferred from the sun to earth?Infererd radiation

Why can it only be transferred through that one type of energy transfer?

A

Inferred radiation.

Conduction and convetion require a medium (particles) but IR does not as it is a EM Wave.