P1.2 Energy and efficiency Flashcards
1
Q
What happens to wasted energy?
A
It is transferred into the surroundings and spreads out so much that it becomes very difficult to do anything useful with it.
2
Q
What is the equation for calculating efficiency?
A
efficiency=( useful energy transferred ÷ energy supplied ) × 100
3
Q
What is the equation for payback time?
A
payback time = cost of energy-saving measure ÷ money saved each year
4
Q
What are three disadvantages of buying energy-saving devices?
A
- initial cost
- use of extra resources to manufacture new device
- cost of disposal of old device.
5
Q
What are two advantages of buying energy-saving devices?
A
- cost efficiency
- saving energy and resources.
