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 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?
Engy 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 6700 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?
A microwave is used for 5 minutes, during which time it is supplied with 180 kJ of energy. What is the power of the microwave?
What is 24 MW in kilowatts?
How many joules are there in 1 kilojoule?
What is joules in kilojoules?
A 60 W incandescent light bulb is left on for 30 seconds. How much energy is supplied to it over this time?
Which of the following is the correct unit for energy?