Question

During short circuiting, the electric current in the circuit-

• A. Becomes very small
• B. Remains unchanged
• C. Increases greatly
• D. Changes continuously

Hint:

Fuse wires and circuit breakers are safety devices designed to protect circuits from the excessive current produced during short circuits.

Answer 1

The Correct Option is C

Concept: A short circuit occurs when a very low resistance path is created between two points of different potential. This bypasses the normal load and allows a huge amount of current to flow. According to Ohm's law, \[ I=\frac{V}{R} \] where \[ I=\text{Current} \] \[ V=\text{Potential Difference} \] \[ R=\text{Resistance} \]

Step 1: Understand what happens during a short circuit. During short circuiting, the resistance becomes extremely small. \[ R \rightarrow 0 \]

Step 2: Apply Ohm's law. Since current is inversely proportional to resistance, \[ I=\frac{V}{R} \] a very small value of \(R\) results in a very large value of \(I\).

Step 3: State the consequence. The excessive current generates a large amount of heat which may:

• Damage electrical appliances

• Melt wires

• Cause electrical fires
Therefore, during short circuiting the current increases greatly.