Electricity Calculations

Calculate the energy released from a battery in a hand vacuum cleaner that was switched on for 45 s. The voltage drop was 6 V and the current was 0.30 A.

• 35 J

• 81 J

• 42 J

• 82 W

Calculate the power rating of an electric toaster that uses 210 000 J while toasting bread for 140 s

• 1500 J

• 1200 W

• 1500 W

• 1300 J

Calculate the percent efficiency of an electric motor that uses 15 000 J of energy to produce

11 500 J of useful movement.

• 76.6%

• 82.3%

• 75.4%

• 23.3%

Calculate the energy used by a coffee maker that has a power rating of 0.900 kW and operated for 17 hours.

• 15.3 kwh

• 17.3 kwh

• 900 kwh

• 1200 kw

Calculate the cost of operating a heater of 1.75kw for 20 hours at rate of $0.13 per kwh?

• $6.75

• $4.55

• $53.43

• $45.53