# Snapquiz - AC vs DC

This is the Snapquiz on AC vs DC. Click here or use the embedded video if you haven't watched the lesson yet.

Question 1. Why do we use AC for mains electricity?

It's the agreed international standard way to generate electricity.
AC electricity flows back and forth from the supply.
It's easy to generate and can be distributed efficiently.
It's less dangerous than DC.

Question 2. What would a DC supply look like on an oscilloscope?

A curved line starting at a high positive potential difference then steadily falling to zero.
A straight line remaining at a single non-zero potential difference over time.
A straight line remaining at a potential difference of zero over time.
A wave going from positive to negative over time.

Question 3. What is DC short for?

Dangerous Current.
Device Current.
Direct Current.
Dilute Current.

Question 4. Which analogy is similar to an AC supply?

The tide regularly coming in and going back out again.
A river flowing in the same direction all the time.
The wind blowing in different directions every day.
The waves on the sea moving up and down at random.

Question 5. What is the mains potential difference and frequency in the U.K?

110V, 60Hz.
110V, 50Hz.
230V, 50Hz.
230V, 60Hz.