Electrician's Licensing Practice Exam

What happens when a specific voltage is applied to an ohmic resistance?

1. The current increases

2. The current decreases

3. The current may remain constant

4. The voltage drops significantly

The correct answer is: The current may remain constant

When a specific voltage is applied to an ohmic resistance, the relationship between voltage, current, and resistance is governed by Ohm's Law, which states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. In a circuit with an ohmic resistor, as the voltage is held constant and applied to the resistor, the current that flows will also be consistent and predictable, depending on the value of the resistance. If the resistor's characteristics remain unchanged, the current should ideally remain constant when the voltage is unchanged. Therefore, it's accurate to say that the current may remain constant when a specific voltage is applied to a purely ohmic resistance. In contrast, other scenarios would involve variations in resistance or other factors that could cause current to change. Constants like temperature can affect resistance in real-world applications, but in the context of a purely ohmic material and under stable conditions, the principle holds that the application of a specific voltage maintaining a consistent resistance will yield a constant current.