Power, work and energy

Instructions:

There are 10 questions.

For the multi-choice questions:

• choose the correct answer
• write down your answer.

For the calculation questions:

• calculate the unknown value
• specify the appropriate unit
• write down your answer.

Note:

• You can print this page and write you answers onto it.

 

1. What unit is used to measure power?

1. Volt.
2. Ampere.
3. Watt.
4. Joule.

 

2. Energy can be defined as ...

1. the rate at which work is done
2. movement against a force or resistance
3. the ability to do work.

 

3. Power can be defined as ...

1. the rate at which work is done
2. movement against a force or resistance
3. the ability to do work.

 

4. Work can be defined as ...

1. the rate at which work is done
2. movement against a force or resistance
3. the ability to do work.

 

5. What is the formula to calculate power?

1. P = V ÷ I.
2. P = I ÷ V.
3. P = V x I.
4. P = I x R.

 

6. How much power does a heating element consume if its supply voltage is 240V and its current draw is 4A?

 

7. What is the current flow to a 36W globe connected to a 6V supply?

 

8. What would be the voltage supply to a 220W electric jug drawing 2A?

 

9. What is the current flow to a 240W globe connected to a 240V supply?

 

10. What would the efficiency be of a 4500W motor that required an input of 7500W to operate?

 

When you have finished:

• show your answers to your trainer
• close this window and choose a new activity from the menu.