___ is indicated on a clamp-on ammeter when placed within the magnetic field produced around a single conductor.

When using a clamp-on ammeter, the device measures the current flowing through a conductor by detecting the magnetic field generated by the electrical current. The principle behind this is that a magnetic field is produced around a conductor when an electric current passes through it. The clamp-on ammeter is designed to pick up this magnetic field and convert it into a measurement of the current.

Therefore, when the clamp is placed around a single conductor, the reading shown on the ammeter indicates the current flowing through that conductor. This function distinguishes it from other electrical measurements like voltage or resistance, which do not operate based on the magnetic field produced by current flow. Voltage measurements would require different tools such as a multimeter in a different configuration, and resistance measures would typically involve isolating a circuit and applying a test voltage in a manner that is not applicable with the clamp-on method. Hence, the correct outcome is that the ammeter indicates the current flowing through the conductor.