Grade 9 Electricity Practice Exam

Measuring current in a circuit requires a device that becomes part of the path the current travels. An ammeter is designed for this purpose: it is connected in series with the circuit, so all the current flows through it. Because an ideal ammeter has near-zero resistance, it doesn't change the current much, and it displays the current in amperes. A voltmeter, on the other hand, is placed in parallel to measure voltage, not current. A galvanometer is a sensitive current detector and is the basic sensing element inside an ammeter, but by itself it isn’t typically used to measure the circuit’s current unless configured as part of a larger instrument. A multimeter can measure current, but it’s a versatile tool that can measure several quantities; when used to measure current, it serves that function through an ammeter-like path, not specifically a dedicated current meter. Therefore, the instrument best suited to measure current in a circuit is the ammeter.