biggest bulb=180mA

Smallest bulb=60mA

Long bulb=45mA

Which circuit has the largest current?

The circuit with the biggest bulb (180mA) has the largest current.

Which circuit has the smallest current?

The circuit with the long bulb (45mA) has the smallest current.

What is the purpose of the switch in this current?

The purpose of the switch is to turn the light on and off.

When you measure an unknown current, you should start with the meter set to a large current scale and then decrease the scale. Explain the purpose of starting with a higher setting.

You should start with a higher setting because starting with a small setting you can break the amp meter by overloading. It is better to start with a higher setting then working your way through the smaller settings so you can get an accurate reading easier.