Why the circuit is short-circuited? Please explain thoroughly.The link for the diagram-     http://i50.tinypic.com/169ke4z.gif

Wilson2014 | eNotes Employee

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A shorted-circuit is where the current in the original circuit flows through another, unintended path. (Different than the misuse of "short-circuit" to describe any electrical malfunction.)

In the diagram, the current would flow from the voltage source and back, crossing only the 2 ohms resistor. There is no current flowing through the 6 ohms resistor because it lies parallel to another path that contains no resistance. Since electrical currents, which are just movements of electrons, tend to flow through a path of least resistance, the path parallel to the path containing the 6 ohms resistor would be the preferred choice of flow. Assuming that the path with the 6 ohms resistor is the intended path and the path with no resistor is the unintended path, this circuit becomes "shorted." The current will only flow through the path of less resistance and avoid the path containing the 6 ohms resistor completely.

Shorted-circuits are generally avoided because of the low resistance to the current flow. The faster a current flows, the more heat is generated, and this can lead to dangerous situations, such as overheating an external material, leading to a fire. It may even cause an explosion.

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