Electrical Power and Energy

What power is needed to generate 2A of current when plugged into a standard US power outlet (120-V)

• 240 W

• 60 W

• 240 V

• 60 A

A 750 Watt hairdryer is used for 15 minutes. Calculate the kWh used. Calculate the energy used.

• 11,250 kWh

• 50 kWh

• .19 kWh

• 5 kWh

Tags

NGSS.HS-PS3-1

If part of an electric circuit dissipates energy at 6 W when it draws a current of 3 A, what voltage is impressed across it?

• 18 V

• 2 kW

• 18 Ω

• 2 V

A room is lit by a 150 watt light bulb. How much does it cost to use for 2.5 hr @ 8 cents/kWh?

• $30

• $4.80

• $0.03

• $3

Tags

NGSS.HS-PS3-1

How much current does a 100‐W lamp draw when connected to 120 V?

• 12000 A

• .12 A

• .83 A

• 12 A

There are 2 A of current in a circuit that has one 1.5 V battery. What is the electric power consumed by the circuit?

• 120 W

• 0.75 W

• 1.3 W

• 3 W

The electric power consumed by a circuit with one light bulb is 6 W. The current in the circuit is 4 A. What is the voltage of the circuit?

• 24 V

• 0.66 V

• 1.5 V

• 150 V

How much energy is consumed by a 120 W light bulb if it is left on for 15 min?

• 1800 kWh

• 0.125 kWh

• .03 kWh

• 18 kWh

Tags

NGSS.HS-PS3-1

An electric heater draws 1100 W of power. Electricity costs 8¢ per kW•h. How much does it cost to operate the heater 3.0 h a day for 30 days?

• $792,000

• $21.42

• $7.92

• $3.87

Tags

NGSS.HS-PS3-1

A refrigerator operates on average for 12 hours a day. If the power rating of the fridge is 200 W, how much electrical energy does the fridge use in one week?

• $24.00

• $16.80

• $2.40

• $8.95

Tags

NGSS.HS-PS3-1