What happens when an electrical circuit is short-circuited?

When an electrical circuit is short-circuited, a large current flows due to the drastic reduction in resistance when an unintended path is created. In a short circuit, the current bypasses the designated load, making it possible for a flow of electricity that is much higher than the circuit is designed to handle. This excessive current can lead to overheating, damage to components, and even the risk of fire.

The other choices do not accurately describe what occurs in a short circuit. A short circuit does not create an open circuit (which would stop current flow entirely), nor does it lead to a significant increase in resistance; in fact, the opposite happens, where resistance drops. Lastly, while the voltage does not drop to zero, the excessive current can cause voltage sag in other parts of the circuit, but this isn't the defining characteristic of a short circuit situation. Thus, the outcome of a large current flowing and potentially causing damage is the correct explanation.