Heating, Ventilation, and Air Conditioning (HVAC ) Electrical Practice Test

How can resistance be calculated in an electrical circuit?

1. R = E x I

2. R = E / I

3. R = I / E

4. R = I x E

The correct answer is: R = E / I

Resistance in an electrical circuit is calculated using Ohm's Law, which states that the voltage (E) across a circuit is equal to the current (I) flowing through it multiplied by the resistance (R). This relationship can be mathematically rearranged to express resistance in terms of voltage and current. The correct formula, R = E / I, indicates that resistance is equal to the voltage divided by the current. In this equation, 'E' represents the voltage in volts, 'I' represents the current in amperes, and 'R' represents resistance in ohms. This relationship is foundational in electrical engineering and helps in analyzing and designing circuits by allowing technicians and engineers to determine how much resistance is in a circuit based on its voltage and current. Other options provided do not align with Ohm's Law. For example, multiplying voltage by current or dividing current by voltage does not yield resistance, as this would violate the principles established by the law. Understanding this principle is vital for anyone working in HVAC systems since it governs how various electrical components, like motors and heaters, operate within the overall system.