Worksheet: Power and Energy
In this worksheet, we will practice using the formula P = E/t to calculate the rate at which energy is transferred by a device given the amount of energy it transfers in a given time.
Which of the following is the correct unit for power?
A kettle is filled with water and turned on. It takes 3 minutes to boil the water, and the kettle is supplied with 324,000 J of energy in this time. What is the power of the kettle?
A 30 mW LED in an electronic circuit is left on for 2 hours. How much energy does it transfer to its environment over this time? Assume that the LED is efficient.
How many watts are there in 1 megawatt?
What is 34 kJ in joules?
Jennifer wants to find out how much electrical power her television needs when it is on. She watches television for a few hours and records how much energy has been supplied to it every half hour. The graph shows her results.
How much energy has been supplied to the television after 3 hours?
What is the power of her television?
What is 6,700 kilowatts in megawatts?
Which of the following is the correct formula for the energy transferred, , in a given time, , for an electrical appliance with a given power, ?
What is 50 MW in watts?
What is 24 MW in kilowatts?
How many joules are there in 1 kilojoule?
What is 5,000 joules in kilojoules?
Which of the following is the correct unit for energy?