Energy

Question 0

What is heat radiation?

Answer 0

The transfer of heat energy by infrared radiation.

Question 1

How can heat energy be transferred?

Answer 1

By radiation, conduction or convection.

Question 2

What types of energy transfer involve the transference of particles?

Answer 2

Conduction and convection

Question 3

What is the main energy transfer in solids?

Answer 3

Conduction

Question 4

What is the main form of heat transfer in liquids and gases?

Answer 4

Convection

Question 5

Infrared radiation can be emitted by……

Answer 5

Solids, liquids and gases.

Question 6

Where is infrared radiation emitted from?

Answer 6

The surface of an object

Question 7

Describe the conduction of heat energy?

Answer 7

It is where vibrating particles pass on their extra kinetic energy to neighbouring particles

Question 8

When does conduction work faster?

Answer 8

In denser solids

Question 9

Describe convection:

Answer 9

It is when the more energetic particles move from the hotter region to the cooler region, taking their heat energy with them.

Question 10

How does an immersion heater work?

Answer 10

See page 14 of CGP book

Question 11

What are convection currents about?

Answer 11

Changes in density

Question 12

What factors affect the rate of reaction so it will be faster?

Answer 12

• higher temperature
• lower density
• larger surface area
• greater airflow over the liquid

Question 13

The rate of condensation will be faster if:

Answer 13

• temperature of gas is lower
• temperature of the surface the gas touches is lower
• density is higher
• airflow is less

Question 14

How are vacuum flasks designed to limit heat transfer?

Answer 14

See page 16 CGP book

Question 15

What is hair standing up on your skin supposed to reduce?

Answer 15

Heat loss by convection

Question 16

How do you work out pay back time?

Answer 16

Initial cost / annual saving

Question 17

Give the formula involving specific heat capacity

Answer 17

E= M x C x temp change

Energy transferred = mass x specific heat capacity x temp change

Question 18

What is specific heat capacity?

Answer 18

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

Question 19

List the 9 types of energy:

Answer 19

Heat
Sound
Light
Nuclear
Thermal
Kinetic
Elastic potential
Gravitational potential
Chemical

Question 20

How do you calculate efficiency?

Answer 20

Useful energy (or power) in / total energy (or power)

Question 21

What is a kilowatt-hour?

Answer 21

The amount of electrical energy used by a 1kW appliance left on for 1 hour.

Question 22

Give the 2 formulas for calculating the cost of electricity

Answer 22

No. Of units (kWh) = power (in kWh) x time (hrs)

AND

Cost = no. of units x price per unit