P2

Question 1

The higher the thermal conductivity of a material, the ____ the rate of energy transfer by conduction across the material

Answer 1

Higher

Question 2

What is thermal conductivity?

Answer 2

A measure of how well a material conducts electricity when heated

Question 3

What does the energy transfer per second through a layer of Insulation material depend on?

Answer 3

• temperature difference across material
• thickness of material
• thermal conductivity of material

Question 4

The larger the temperature difference the ____ the rate of energy transfer by conduction

Answer 4

Higher

Question 5

The ____ the material, the lower the rate of energy transfer by conduction

Answer 5

Thicker

Question 6

How can you reduce energy loss in homes?

Answer 6

• loft insulation
• cavity wall insulation
• double glazing
• draft excluders

Insulation traps air in small pockets, reducing rate of energy transfer by conduction.

Question 7

How can we reduce the cost of producing energy in the home?

Answer 7

• energy efficient boiler
• install solar panels

Question 8

What is the specific heat capacity of a substance?

Answer 8

The amount of energy required to raise the temperature of 1kg of the substance by 1°C

Question 9

Describe the specific heat capacity RP

Answer 9

1. Measure mass of block
2. Measure start temperature of the block using a thermometer
3. Turn on powerpack, and increase temperature of block using an immersion heater
4. Measure energy input using a Joulemeter
5. Record end temperature and calculate the temperature difference
6. Find specific heat capacity

Question 10

How can you improve the specific heat capacity rp?

Answer 10

• Wrap block in insulation to minimise heat loss
• Repeat investigation to calculate an average and reduce error

Question 11

Some students want to investigate the effectiveness of different materials as thermal insulators. What is the IV, DV and CV?

Answer 11

IV- material
DV- Temperature change
CV- Thickness of material, volume and temperature of water, time allowed for water to cool

Question 12

Some students want to investigate the effectiveness of different materials as thermal insulators. Suggest a method for them to follow

Answer 12

1. Cover container in insulating material
2. Pour 200ml of water into container using a measuring cylinder
3. measure start temperature with a thermometer
4. time 10 mins
5. measure end temperature and calculate the difference
6. repeat for the other materials

Question 13

Some students want to investigate how the thickness of a material effects the rate of energy transfer. What is the IV, DV and CV?

Answer 13

IV- Thickness
DV- Temperature change
CV- Material, volume and temperature of water, time allowed to cool

Question 14

Some students want to investigate how the thickness of a material effects the rate of energy transfer. Suggest a method for them to follow

Answer 14

1. Cover container in 1 layer of insulating material
2. Pour 200ml of water into container using a measuring cylinder
3. measure start temperature with a thermometer
4. Record temperature every 30 secs for 10 minutes using a stopwatch
5. Repeat for 2,3,4,5 layers of insulating material

Question 15

What do the thermal insulation results show?

Answer 15

the thicker the material, the slower the rate of energy transfer from container

Question 16

What is the equation for specific heat capacity?

Answer 16

change in thermal energy (J) = mass (kg) x specific heat capacity (J/kg degree C) x change in temperature (degrees C)