Energy

Question 1

1. List the 8 energy stores:
2. Which 4 ways can energy be transferred?
3. When we talk about energy, what is a ‘system’?
4. What happens to energy when a system changes?
5. What is a closed system?
6. What might be a better way of describing ‘wasted energy’?

Answer 1

1. Thermal, radiant, nuclear, chemical, electrical, kinetic, elastic potential, gravitational potential.
2. Heat, chemically, radiation, mechanically
3. An object or group of objects that can transfer energy
4. Energy gets dissipated
5. A complete system where no energy can be added or gained
6. Dissipated

Question 2

1. State the formula for kinetic energy:

2. State the formula for calculating gravitational potential energy

Answer 2

1. Ke=0.5xmassxvelocity^2

2. gpe=massxgravitational field strengthxheight

Question 3

1. What is meant by the specific heat capacity of a substance?
2. What is the equation linking energy transferred to specific heat capacity

Answer 3

1. Amount of energy needed to change the state of 1kg of a stub stance without changing the temperature
2. Work done=massxchange in temp

Question 4

1. Give a definition for power
2. State the 2 formulae for calculating power
3. What is the unit for power?
4. What is the Watt equivalent to in terms of energy?

Answer 4

1. The amount of energy transferred within a given time
2. P=e/t p=w/t
3. Watts
4. 1 joule per second

Question 5

1. What is the formula for calculating efficiency for energy transfers?
2. List 2 ways to increase efficiency of energy transfer?
3. Why is useful energy output not equal to total energy output?
4. What is an exception to this?

Answer 5

1.Efficiency = useful energy output ÷ total energy input
2.Increase useful energy output
Decrease wasted energy output
3.Increase useful energy output
Decrease wasted energy output
4.Electric heaters transfer all the energy to useful thermal energy stores

Question 6

1. What is meant by a non-renewable energy resource?
2. What are the three types of fossil fuels?
3. Name the other non-renewable energy resource
4. What is meant by a renewable energy resource?
5. State 3 major uses of different energy resources

Answer 6

1.An energy source that will eventually run out
2.Crude oil, natural gas and coal;
Fossil fuels are non-renewable
3.Nuclear energy
4.These sources can be renewed as they are being used and will not run out
5.Transport
Electricity generation
Heating