Washington Esthetician State Board Practice Exam

What does an increase in voltage across a fixed resistor result in?

1. Decreased current flow

2. Increased heating

3. No effect on current

4. Increased insulation resistance

The correct answer is: Increased heating

An increase in voltage across a fixed resistor results in increased heating due to the principles governed by Ohm's Law and the power dissipation in resistors. According to Ohm's Law, the current (I) through a resistor is directly proportional to the voltage (V) across it, given by the equation V = IR, where R is the resistance. When the voltage increases while the resistance remains constant, the current also increases. The power dissipated by a resistor, which corresponds to the heating effect, is calculated using the formula P = IV or P = V^2/R. Hence, as the voltage increases, the current increases as well, which leads to a higher power dissipation (or heating) in the resistor. This increased power results in the resistor producing more heat. In practical terms, this is important for understanding how components manage thermal energy, and why overheating can damage electronic components or affect their performance.