Energy and Power

What is power?

The energy transferred by an appliance in a certain amount of time.

What is the equation for power?

Power (W) = Energy (J) / Time (s).

How can you calculate energy transferred?

Energy (J) = Power (W) × Time (s).

If a 2000 W hairdryer is on for 60 seconds, how much energy is transferred?

120,000 joules (2000 W × 60 s).

If a 55 W fan is on for 60 seconds, how much energy is transferred?

3,300 joules (55 W × 60 s). [Note: the video text says 330, but 55×60 = 3,300; likely a typo in transcript. Flashcards follow the video equation.]

If an 800 W microwave is on for 60 seconds, how much energy is transferred?

48,000 joules (800 W × 60 s).

What unit do energy companies use to measure household energy usage?

Kilowatt hours (kWh).

What is the equation for energy in kilowatt hours?

Energy (kWh) = Power (kW) × Time (h).

How many watts are in one kilowatt?

1,000 watts.

How can you save energy when choosing appliances?

Choose appliances that have the same performance but a lower power rating.

Why does a lower power rating save energy?

Lower power means less energy being used over time (power = energy/time).

What are two ways to save energy and reduce costs mentioned?

Use appliances for a shorter amount of time, and insulate your house.

What are examples of home insulation mentioned?

Cavity wall insulation, loft insulation, draught excluders, double glazing.

Why is insulating your house important for saving energy?

To reduce the heat that is lost from your house, saving money and energy on heating.