Energy and efficiency Flashcards
1
Q
What is the unit for energy?
A
Joules (J).
2
Q
State the 9 forms of energy.
A
Sound, Light, Heat, Electrical, Kinetic movement, Elastic, Chemical , Gravitational and Nuclear.
3
Q
What form is energy normally in when it is wasted?
A
When energy is transferred some of it is always ‘wasted’ usually as heat or sound.
4
Q
Why is wasted energy difficult to use again?
A
When energy is wasted it eventually heats up the surroundings becoming spread out.
5
Q
Define efficiency.
A
how well an object transfers input energy into useful energy.
6
Q
What is the equation cost effectiveness payback time?
A
cost effectiveness (payback time) = Initial cost / yearly saving
