physics electricity

2013-03-30 3:06 am

janet has bought a refrigerator and a washing machine affixed with grade 1

grade 1 level appliances are most energy efficient

grading level ------ 3.......................5
washing machine 20%.................40%

the above information shows the approximate percentage of electricity saved as compared to those with different grading levels

the electric energy required per load of janet's washing machine is 0.6kwh. janet
waches her clothes 3 times a week , compared to a grade 5 level washing machine with the same functions and electric power, what is her annual electricity saving? suppose there are 52 weeks in a year

回答 (1)

天同

2013-03-30 3:58 am

✔ 最佳答案

Electricity consumption in a year by using Janet's washing machine
= 0.6 x 3 x 52 kWh = 93.6 kWh

Hence, electricity consumed by a grade 5 level washing machine in a year
= 93.6/(1-0.4) kWh = 93.6/0.6 kWh = 156 kWh

Therefore, annual electricity saving by using a grad 1 level machine
= (156 - 93.6) kWh
= 62.4 kWh

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