Which electrical value cannot be tested using a VOM (multimeter)?

The value that cannot be directly tested using a VOM (voltage, ohm meter), commonly known as a multimeter, is watts. While the multimeter can measure voltage and resistance directly, calculating wattage requires additional information that isn't directly measured by the multimeter alone.

Watts represent the rate of energy consumption or the power in an electrical circuit, which can be calculated using the formula: Power (watts) = Voltage (volts) × Current (amps). This means that to determine power, both voltage and current must be measured separately with the multimeter, then combined mathematically. In contrast, voltage and resistance can be read directly from the multimeter, and amperage can also be measured using the multimeter in specific configurations, such as in series with the circuit. Thus, watts cannot be measured directly, making this option the correct answer for the question.