P2 - Energy Transfer by heating

Question 1

What is thermal conductivity?

Answer 1

• How quickly energy is transmitted throguh thermal conduction
• Particles bump into each other and free electrons can transfer energy

Question 2

How can the amount of energy stored or released from a system as temperature changes be calculated?

Answer 2

Change in temperature=mass times specific heat capacity times change in temperature

Question 3

What is the unit for mass?

Answer 3

kg

Question 4

What is the unit for specific heat capacity?

Answer 4

J/kg C

Question 5

What is specific heat capacity?

Answer 5

Amount of energy needed to raise the temperature of 1kg of the substance by 1 degree celsius

Question 6

The higher the thermal conductivity…

Answer 6

The higher the rate of energy transfer by conduction across the material

Question 7

What is a conductor?

Answer 7

• The process by which energy is transferred through a material
• Metals eg

Question 8

What do insulators do?

Answer 8

Reduce unwanted energy loss by insulating with low thermal conductivity so less energy is transferred by conduction

Question 9

What happens to energy wasted in a home?

Answer 9

Dissipates into environment in the form of thermal energy

Question 10

What is infrared radiation?

Answer 10

Occurs when all emits and absorbs infrared radiation which is reflected by shiny surfaces

Question 11

The higher the temperature or surface area..

Answer 11

the more infrared radiation emitted

Question 12

What is a black body?

Answer 12

• A theoretical object which absorbs 100% of radiation
• A perfect one would not reflect or transmit and would be a perfect emitter

Question 13

What do greenhouse gases do?(2)

Answer 13

1. Greenhouse gases absorb infrared radiation emitted by surface area of the Earth and prevents escape
2. they re-emit back to the surface and increase the Earth’s temperature