# Lesson Worksheet: Alternating Current Physics • 9th Grade

In this worksheet, we will practice identifying alternating currents and calculating the properties of alternating currents.

**Q1: **

Which of the following statements correctly describes what is meant by the term “alternating current”?

- AAn alternating current is an electric current which periodically reverses direction.
- BAn alternating current is an electric current that gradually decreases over time.
- CAn alternating current is an electric current that varies periodically but does not change direction.
- DAn alternating current is any electric current that changes direction at least once.
- EAn alternating current is an electric current that gradually increases over time.

**Q5: **

The graph shows the current in an incandescent bulb over time. The peak value of the current is 0.15 A. How much time passes between each time the current reaches its peak value?

**Q6: **

The graph shows the current through an incandescent bulb over time.

How much time passes between each time the current changes direction?

**Q7: **

The graph shows the current through a resistor over time.

How many times does the current change direction in the first five seconds?

**Q8: **

The graph shows the current through a resistor over time.

At what time on the graph does the current change direction?

**Q9: **

Each of the following graphs shows the current in a wire over time. Which graph shows an alternating current?

- A
- B
- C
- D
- E