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Home Minds On Electric Circuits Mission EC2 Voltage Help Help 8

Mission EC2 Voltage

The Question

When the light bulb in your lamp no longer works, it is because the bulb has _____.

Physics Rules

Requirements for an Electric Circuit:
In order to establish an electric circuit through which charge flows, it is necessary to meet the following two requirements:
  • There must be a closed conducting path that extends from the positive terminal to the negative terminal.
  • There must be a source of energy capable of doing work upon an electric charge to move the charge from the low energy terminal to the high energy terminal.

Think About It

Two requirements must be met in order for an electric circuit to be established. There must be an energy supply that maintains an electric potential difference across the two ends of the electric circuit. And there must be a closed conducting loop that connects the positive terminal and the negative terminal of the energy source. When a light bulb has burned out, the requirement of a closed conducting loop is no longer met. You can often look inside the bulb and view the coiled filament dangling from one of the vertical posts. If it is not dangling from the vertical posts, you will notice that there is no connection from one of the posts to the other posts. If you shake the bulb, you can often hear the coiled filament moving around in the bottom of the bulb. The burning or loss of the filament between the two vertical posts opens up the circuit at that location. There is no longer a means by which charge can flow in a circuit between the two terminals of the battery.

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