How can resistance be calculated?

To calculate resistance in an electrical circuit, Ohm's Law is used, which states that resistance (R) is equal to voltage (E) divided by current (I). This relationship is fundamental in understanding electrical circuits and is expressed mathematically as R = E / I.

When you apply this formula, voltage represents the electrical potential difference, while current represents the flow of electric charge. By rearranging this equation, you can solve for resistance, which indicates how much the material opposes the flow of current. This understanding is crucial in HVAC systems, where proper calculations are necessary to ensure efficient operation of electrical components like motors and controls.

The other options presented do not conform to Ohm's Law and thus do not provide a valid method for calculating resistance. Understanding this factual basis is essential for anyone working with electrical systems in the HVAC field, as accurate resistance values impact the overall performance and safety of those systems.