Back to P7 Home

P7: Quiz 1 – Answers

P7: Quiz 1 – Answers

1)

a) Current is the flow of electrical charge per second

b) Amps (A)

2) The two things are:

3)

a) Potential difference is the driving force that pushes the electrical charge around a circuit

b) Volts (V)

4) charge flow = current x t

Q = It

Q is charge flow measured in coulombs (C), I is current measured in amps (A) and t is time measured in seconds (s)

5)

a) 360 C

b) 2,400 C

6) 6,804 C

7) 55 seconds

8) 24 minutes

9) 4,500 C

10) 4.5 hours

a) Current is the flow of electrical charge per second

b) Amps (A)

2) The two things are:

- The circuit must be closed/ complete
- There must be a source of potential difference (such as a cell or battery)

3)

a) Potential difference is the driving force that pushes the electrical charge around a circuit

b) Volts (V)

4) charge flow = current x t

Q = It

Q is charge flow measured in coulombs (C), I is current measured in amps (A) and t is time measured in seconds (s)

5)

a) 360 C

b) 2,400 C

6) 6,804 C

7) 55 seconds

8) 24 minutes

9) 4,500 C

10) 4.5 hours

**Questions**

1)

a) Give a definition for current.

b) What unit do we measure current in?

2) What two things are needed for electrical charge to flow around a circuit?

3)

a) Give a definition for potential difference.

b) What unit do we measure potential difference in?

4) Write the equation that links current, charge flow and time. Give the units for each of the variables.

5) A device in a circuit has a current of 8 A.

a) Calculate the charge flow when the circuit is on for 45 seconds.

b) Calculate the charge flow when the circuit is on for 5 minutes.

6) A device in a circuit has a current of 6.3 A. What is the charge flow if the circuit is on for 18 minutes.

7) A current of 3 A passes through a bulb. The current is on for an unknown period of time and the charge flow during this period of time is 165 C. Calculate how long the current is on for. Give your answer in seconds.

8) A device has a current of 9 A passing through it. The current is on for an unknown period of time and the charge flow during this period of time is 12,960 C. Calculate how long the current is on for. Give your answer in minutes.

9) The current for a laptop charger is 0.5 A. Work out the charge flow if the laptop charger is charging a laptop for 2.5 hours.

10) A fridge has a current of 15 A. The fridge is on for an unknown period of time. The charge flow during this period of time is 243,000 C. Calculate how long the fridge is on for. Give your answer in hours.