🔍 Key Concepts

• Ammeter basic principle – how an ammeter measures current (small internal movement that can only handle limited current) • Shunt resistor function – why we place a low‑resistance path in parallel with the meter movement • Difference between internal shunt (built-in) and external shunt (separate, often physically larger)

💭 Think About

• Think about what happens to a small, delicate meter movement when you must measure very large currents. What role does heat play in that situation? • Which option best explains a practical reason shipboard engineers might mount the shunt away from the meter itself? Consider temperature, space, and current-carrying capacity. • Ask yourself: does using an external shunt change the sensitivity of the meter movement, or mainly how the heavy current and heat are handled?

✅ Before You Answer

• Verify which choice deals with heat and high current in the shunt, not with power factor or resistance magnitude alone. • Eliminate any options that confuse current measurement with power factor (reactive power) – those are usually concerns with wattmeters, not simple ammeters. • Confirm that an external shunt allows the high current path and heat to be handled away from the delicate meter movement.