energy Flashcards
1
Q
How many joules are in one kilojoule
A
1000J
2
Q
Where do humans get their energy from?
A
Food
3
Q
Name the three forms of potential (stored) energy.
A
Gravitational, elastic and chemical
4
Q
What is kinetic energy?
A
Moving
5
Q
Write out the law of conservation of energy.
A
Energy cannot be created or destroyed it can only be changed from one form to another
6
Q
What is a transducer?
A
A device that converts energy from one form to another
7
Q
Write out the equation for percentage efficiency.
A
Percentage efficiency = useful energy output /total energy input x 100
8
Q
Calculate the percentage efficiency. A light bulb uses 400J of electrical energy and converts 250J into light energy and 150J into heat energy.
A
250 /400 x 100 = 62.5%
