A short circuit is characterized by what resistance in the branch?

• A. Zero or very low resistance
• B. High resistance
• C. Infinite resistance
• D. Normal resistance

Answer: (A)

Short circuits happen when current finds a path with almost no resistance, so a lot of current flows through that branch and bypasses the intended load. The key feature is that the resistance in that branch is essentially zero or very low, so I = V/R becomes a very large current (limited only by the source and wiring). If the resistance were high, only a small amount of current would flow; if it were infinite, no current would flow at all; normal resistance would mean the circuit works as designed. So the branch resistance being zero or very low is what defines a short circuit.