Circuit Physics Example 1

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Example 1

easy
A simple circuit has a 9 V9 \text{ V} battery and a 3 Ω3 \text{ } \Omega resistor. What is the current in the circuit? What happens if the circuit wire is cut?

Solution

  1. 1
    Apply Ohm's law: I=VR=93=3 AI = \frac{V}{R} = \frac{9}{3} = 3 \text{ A}.
  2. 2
    The current flows from the positive terminal through the resistor and back to the negative terminal.
  3. 3
    If the wire is cut, the circuit is open (broken) and no current flows. A complete loop is required for current to flow.

Answer

I=3 AI = 3 \text{ A}
A circuit is a complete conducting loop through which electric current can flow. Breaking the loop at any point stops all current flow. The battery provides the energy (EMF) to drive current around the circuit.

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