In an introductory discussion of electric current, two common sources of electric current are generators and which of the following?

• A. Insulators such as rubber
• B. Resistors creating current without a voltage source
• C. Batteries (electrochemical cells)
• D. Capacitors acting as steady current sources indefinitely

Answer: (C)

Verified step by step guidance

1. Understand the concept of electric current: Electric current is the flow of electric charge, typically carried by moving electrons in a conductor.
2. Identify common sources of electric current: Generators convert mechanical energy into electrical energy, producing current, while batteries (electrochemical cells) convert chemical energy into electrical energy, providing a steady current.
3. Analyze the options given: Insulators like rubber do not conduct electricity and thus cannot be sources of current; resistors do not create current but rather limit it; capacitors store and release charge but do not provide a steady current indefinitely.
4. Conclude that the two common sources of electric current discussed in introductory physics are generators and batteries (electrochemical cells).
5. Remember that batteries provide a voltage source that drives current through a circuit by chemical reactions inside the cell.