Power Calculations

An electric rice cooker rated 800W, 230V is switched on for 30 minutes. Calculate the cost of energy that is used by the rice cooker if the cost per kWh is 30sen.

• RM12

• RM0.12

• RM1.20

• RM120

You generate 10 Watts of power when you move a weight in 4 seconds. How much work did you do?

You do 90 joules of work in 30 seconds. How much power have you generated?

Tags

NGSS.MS-PS3-5

A girl weighs 400 N. She runs up a flight of stairs of height 5 m in 4 seconds. Her power is:

Tags

NGSS.MS-PS3-4

If a light bulb consumes 100 W and is used for 10 hours, how many kilowatt-hours of energy does it consume?

• 10 kWh

• 1 kWh

• 0.1 kWh

• 1000 kWh

A refrigerator uses 250 W of power and runs for 24 hours a day. How much energy does it consume in one day?

• 6 kWh

• 60 kWh

• 600 kWh

• 0.6 kWh

Calculate the energy consumption in kilowatt-hours for a device that uses 1500 W for 2 hours.

• 0.3 kWh

• 3 kWh

• 30 kWh

• 300 kWh

If an oven uses 2000 W (2 kW) and is operated for 3 hours, how many kilowatt-hours are used?

• 6 kWh

• 600 kWh

• 60 kWh

• 0.6 kWh

Tags

NGSS.MS-PS3-5

A washing machine uses 500 W of power. If it runs for 4 hours, how many kilowatt-hours of energy does it consume?

• 0.5 kWh

• 2 kWh

• 20 kWh

• 200 kWh

How many kilowatt-hours are consumed if a 750-W air conditioner runs for 8 hours?

• 0.75 kWh

• 7.5 kWh

• 6 kWh

• 60 kWh