ScPhys Practical Electricity Quiz 1

An electric heater takes a current of 4 A from a 250 V supply when operating normally. How long would it take the heater to convert 400 000 J of electrical energy?

• 400 s

• 1 000 s

• 1 600 s

• 100 000 s

Electric energy produced by light a bulb with resistance of 6 ohm when it is passed by electric current for 60 second is 1440 J, the electric current flowing through the light bulb is ….

• 4 A

• 3 A

• 2 A

• 1 A

The cost of electricity is 27 cents per kWh. What is the cost of using a 1000–1200 W iron at maximum power for 45 minutes?

................... cents (3.s.f)

The cost of using electricity in a household in a 30 day-month is $165.

What is the cost of a unit electricity if the only appliance used was a 2 500 W

air-con operated from 9 pm to 7 am daily?

................... cents

Calculate the energy consumption of an electrical appliance that consumes 500 watts for 5 hours in kWh.

___________ kWh

1. Calculate the annual cost of operating a ceiling fan that consumes 75 watts for 8 hours daily, with electricity priced at $0.18 per kWh in 2 d.p

$ ______________

1. Calculate the monthly cost (1 month = 30 days) of operating a hairdryer for 15 minutes daily, consuming 1200 watts, with electricity priced at $0.25 per kWh (in 3 s.f.)

$ ___________