# 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?