Question

At the time of short circuit the current in the circuit :

• A. reduces substantially
• B. does not change
• C. increases heavily
• D. vary continuously

Hint:

Think of Ohm's Law: Current = Voltage / Resistance. "Short circuit" = Resistance becomes very, very small. If you divide the same voltage by a much smaller resistance, the current becomes much, much larger.

Answer 1

The Correct Option is C

Concept: A short circuit is a low-resistance path unintentionally created in an electrical circuit. Ohm's Law (\(I = V/R\)) helps understand its effect on current. Step 1: What is a short circuit? A short circuit occurs when the current bypasses its intended path (the load, like a bulb or appliance) and instead flows through an alternative path with very low resistance. For example, if the live and neutral wires touch directly. Step 2: Applying Ohm's Law (\(I = V/R\))
\(V\) is the voltage of the source (e.g., 220V).
\(R\) is the resistance of the circuit.
\(I\) is the current flowing. In a normal circuit, the load provides a certain resistance (\(R_{\text{load}}\)). In a short circuit, the resistance of the path (\(R_{\text{short}}\)) becomes extremely small (close to zero). Step 3: Effect on Current Since \(I = V/R\): If \(R\) becomes very small (as in \(R_{\text{short}}\)), and \(V\) remains constant, the current \(I\) must become very large. \(I_{\text{short}} = V / R_{\text{short}}\). Since \(R_{\text{short}}\) is tiny, \(I_{\text{short}}\) is huge. This is why the current "increases heavily." Step 4: Consequences This large current can cause overheating of wires (due to \(P=I^2R\) heating effect), leading to melting insulation, fires, or damage to the power source. Protective devices like fuses or circuit breakers are designed to break the circuit if such high currents occur.