Gas Fitter Practice Test

An ammeter can read which of the following?

1. Pressure drop

2. Conductor magnetic field

3. Load in parallel wires

4. Direct power across loads

The correct answer is: Conductor magnetic field

An ammeter is specifically designed to measure the electrical current flowing through a circuit. It works by being connected in series within the circuit, allowing it to accurately gauge the amount of amperes (current) being drawn. The notion that an ammeter can read a conductor's magnetic field is grounded in the principle that current flowing through a conductor generates a magnetic field around it. While the magnetic field itself isn't what the ammeter reads directly, the operation of measuring current can be related to the magnetic field generated by that current. Some advanced ammeter designs may utilize magnetic sensing technologies to infer current levels based on the associated magnetic fields, thus linking the two concepts in practice. The other options do not pertain to the function of an ammeter. For instance, pressure drop would relate to fluid dynamics rather than electrical current, load in parallel wires pertains to how current is shared among parallel connections rather than being measured directly, and direct power across loads would generally involve measuring voltage and current together to calculate power, not something an ammeter itself does. Hence, the ammeter's primary role is to measure current, and its association with a magnetic field reinforces the relationship between current flow and magnetic induction.