Final answer:
An Ammeter, Voltmeter, or a multimeter with continuity and resistance measurement functions are used to test for shorts, opens, and resistance in cables.
Step-by-step explanation:
To verify if the cable has a short, an open, or too much resistance to adequately pass voltage through, an Ammeter and a Voltmeter (or a multimeter that can measure both) are commonly used. For detecting a short or an open, a continuity test function found on many multimeters can be used. If the multimeter emits a tone, the circuit is continuous (no open). If there is no tone, the circuit may have an open. To check for resistance, the multimeter can be set to measure Ohms (the unit of resistance), and if the resistance is too high, it would indicate too much resistance obstructing the flow of electricity. In a school setting, apparatus such as battery testers and small load resistors can help understand the behavior of voltage and current in a circuit when dealing with resistors in series, as per the aim to test the effects of additional resistors on current and voltage.