Final answer:
In the context of using a multimeter, the probes should be in contact either directly or through another conductor. Key instruments include an ohmmeter for resistance and a voltmeter for potential difference, which are connected to a circuit without significantly altering it.
Step-by-step explanation:
The correct completion for the sentence would be 'contact with the multimeter probes needs to be probe to probe or through another conductor'. In physics, specifically when measuring electrical quantities, a multimeter is an essential tool that can measure voltage, current, and resistance. Contact between the probes can be either direct, which is probe to probe, or through a conductor that completes the circuit for the current to pass through.
An ohmmeter is typically used to measure resistance and must be connected across the component isolated from the circuit. A voltmeter measures voltage and is connected in parallel with the component to ensure it experiences the same potential difference, without significantly altering the circuit. Activity: Using meters suggests practicing with meters by connecting them in circuits, starting on the largest scale to prevent meter damage.