1. 5 1 2 6 3 7 4 Efficiency Hair dryer TV Lamp Toy Radio Heater Answer
Complete this Sankey diagram for a coal fired power station
100 % electrical
50 % kinetic
40 % heat
10 % sound
Draw Sankey diagram
Energy In:
100 %
Chemical
Energy Out:
40 % Electrical
50 % Heat
10 % Sound
Answer TV
Energy transferred = power x time
kilowatt hours kilowatts hours
How efficiency is the hair dryer?
Answer
Lamp
Label the energy
Calculate the efficiency
The TV is rated at 900 Watts
How much will it cost to watch it for 2 hours? ( 1 kilowatt hour = 20p)
Toy
Efficiency = Energy usefully transferred x 100
Total energy supplied
Answer
Answer
Percentage
Decimal
Elastic potential = 200 Joules
Sound = 30 Joules
Heat = 70 Joules
Movement = 100 joules
How efficient is this toy?
Radio
Energy in:
200 Joules electrical
Energy out:
40 Joules - light
80 Joules - sound
80 Joules - heat
Draw a Sankey diagram
Heater
This heater is rated at 3 kilowatts
It is turned on for 3 hours
How much does it cost?
Answer
Mains electricity is 230 V
Calculate the current
Answer
Power = voltage x current
Watts Volts Amps