5.5 Appliances and Efficiency Flashcards
1
Q
How do you calculate efficiency
A
output/input x 100
2
Q
Why is there never 100% efficiency
A
transfer energy by heat to the surroundings
electrical - waste energy due to friction between their moving parts
3
Q
how to work output power
A
efficiency x input power
4
Q
Why do we use kilowatt hour
A
instead of joules so it does not give large numbers on bills
5
Q
how to work out number of kilowatt hours used
A
energy used/energy in kilowatt hour
power (Kw) x time
