3NT Chapter 4 Electricity Part III

3NT Chapter 4 Electricity Part III

Multiple Choice

What does power mean?

• Joules transferred per second
• Electron flow per second
• Speed of electrons
• Electron energy

Multiple Choice

kWh stand for

• kilowestohm

• kilometwer

• kilowatt hour

Multiple Choice

What is the SI unit of power?

• Ampere (A)
• Volts (V)
• Joule (J)
• Watt (W)

Multiple Choice

Which of the following is the amount of energy used per unit time?

• power
• work done
• electrical energy

Fill in the Blank

An electric water heater uses 10 000 J of energy in 4 s. Calculate the power.

Fill in the Blank

A hairdryer with a power of 1.5 kW is used for 10 s.

Calculate the electrical energy needed

Multiple Choice

An air-con, rated 1.8 kW 240 V, is switched on for 10 minutes. Calculate the energy used.

• 1 080 000 J

• 144 000 J

• 2400 J

• 18 J

Multiple Choice

A toaster, rated 1500 W 240 V, is switched on for 15 minutes. Calculate the energy used.

• 3600 J

• 22 500 J

• 216 000 J

• 1 350 000 J

Multiple Choice

Calculate the electrical energy used by bulb X in 2 minutes.

• 12 J

• 24 J

• 1440 J

• 720 J

Multiple Choice

Calculate the power of bulb X.

• 2 W

• 6 W

• 8 W

• 12 W

Multiple Choice

A space heater plugged into a 120 V outlet carries a current of 12.5 amps. The heater is run for 4 hours. How much energy is used by this heater?

• 6000 kWh

• 6 kWh

• 38.4 kWh

• 2.4 kWh

Fill in the Blank

A 2400 W water heater was used for 15 minutes.

Calculate the electrical energy in kWh consumed by the water heater.

Fill in the Blank

A 1200 W iron was switched on for 3 hours.

Calculate the electrical energy consumed by the iron in kWh.

Fill in the Blank

A 1.2 kW microwave oven was used for 2 hours.

What is the electrical energy in kWh consumed by the oven?

Fill in the Blank

A 0.40 kW lamp was turned on for 8 hours.

What is the electrical energy in kWh consumed by the lamp?

Fill in the Blank

Calculate the power of the light bulb Q.

Fill in the Blank

Calculate the power of the light bulb P.

Multiple Choice

An air conditioner has a power rating of 1200 W. How much energy does it consume in 8 hours?

• 0.15 kWh

• 150 kWh

• 9600 kWh

• 9.6 kWh

Multiple Choice

An air conditioner has a power rating of 1200 W. Assume that each unit costs 24 cents, what is the cost of using the air conditioner for 8 hours?

• $0

  $0.036

• $36

• $2304

• $2.30

Multiple Choice

If you have 26 light bulbs in your home, each 60 watts, how much does it cost to operate them, on average, for 2.5 hours a day, for a month? The cost of electrical energy from the utility company is $0.100496.

• $391.93

• $11,578.03

• $15.07

• $11.75

Multiple Choice

How much does it cost to operate a TV for a month if the TV uses 110 V in a 0.33 amp circuit and is operated for 6 hours a day. The cost per kWH is $0.08112

• $530.04

• $4.87

• $0.02

• $0.53