Unit 1 Physics- Assignment 3 Energy Transfers
Efficiency of a Kettle
Power (Watts): ........3000................
Time used (seconds): .....160.........
Electrical energy input: = Power x Time = 3000 x 160 = 480,000
Volume of water heated (cm3): ...1100 ...NB: must be above kettle MIN
mark
(note 1 cm3 = 1 ml)
Mass of water (grams) (1 cm3 has a mass of 1 g): .............1100.......g
Mass of water (kilograms): ........11.............................................kg
Water temperature before heating: ..................
Water temperature after heating: ........22.0-degree C .............
Change in temperature: ........100-degree C ...........................
Specific heat capacity of water = 4200 J kg-1 oC-1
Energy transferred to water:
= mass (kg) x specific heat capacity x change in temperature
=1.1 x 4200 x 78
= 360,360
Efficiency of equipment = Energy transferred to water x 100%
Electrical energy input 360,360 x 100=75.075 = 75 %
480,000
Efficiency of a Kettle
Power (Watts): ........3000................
Time used (seconds): .....160.........
Electrical energy input: = Power x Time = 3000 x 160 = 480,000
Volume of water heated (cm3): ...1100 ...NB: must be above kettle MIN
mark
(note 1 cm3 = 1 ml)
Mass of water (grams) (1 cm3 has a mass of 1 g): .............1100.......g
Mass of water (kilograms): ........11.............................................kg
Water temperature before heating: ..................
Water temperature after heating: ........22.0-degree C .............
Change in temperature: ........100-degree C ...........................
Specific heat capacity of water = 4200 J kg-1 oC-1
Energy transferred to water:
= mass (kg) x specific heat capacity x change in temperature
=1.1 x 4200 x 78
= 360,360
Efficiency of equipment = Energy transferred to water x 100%
Electrical energy input 360,360 x 100=75.075 = 75 %
480,000
