Electrical power test questions

1

What is the main energy transformation in a cooker?

2

What is the main energy transformation in a toaster?

3

Which of the following is the correct equation for calculating electrical power?

4

What power rating should a kettle that uses \(20\, 000\, J\) of energy in 10 seconds have?

5

What is the typical power rating of a hair-dryer?

6

What is the typical power rating of a fridge?

7

What happens to energy during energy transformations?

8

In what form is energy generally lost to the surroundings?

9

How do we calculate efficiency?

10

What is the percentage efficiency of an electric drill that uses \(300\, J\) of electrical energy each second but only does \(100\, J\) of useful work?