Question 6A306

A short circuit across any part of a transformer winding creates a path of extremely low resistance. According to Ohm's Law (I = V/R), if the resistance (R) drops significantly while the voltage (V) remains relatively constant, the current (I) will rise to an excessive value. This high current draw on the secondary side immediately reflects back to the primary winding, causing an equally excessive current from the power source. Circuit breakers and fuses are essential safety devices designed to detect such overcurrent conditions. Their immediate function is to "trip" or "blow," thereby opening the circuit and interrupting the flow of power to prevent overheating, damage to the transformer, potential fire hazards, and protect the power supply. Therefore, the immediate effect is a surge in current, followed by the activation of protective devices. Option B is incorrect because while a sustained short *could* burn the transformer, it would only happen if the protective circuit breaker or fuse failed to trip. The immediate effect is the current surge and protection activation. Option C is incorrect; a short circuit always causes current to *increase*, not decrease, due to the extremely low resistance path created.