What does resistance in a circuit cause?

Resistance in a circuit is a fundamental concept in electrical engineering that directly affects how electricity flows. When resistance is present in a circuit, it impedes the flow of electric current. This impedance leads to two primary effects: a voltage drop and a decrease in current.

A voltage drop occurs as the electric current encounters resistance. According to Ohm's Law, which states that voltage (V) equals current (I) multiplied by resistance (R), an increase in resistance results in a corresponding decrease in voltage across the component. This means that as current flows through a resistor, the voltage decreases due to the energy being used to overcome that resistance.

Additionally, resistance also causes a decrease in current. For a fixed voltage supply, an increase in resistance will cause a reduction in the amount of current flowing through the circuit, again as described by Ohm's Law. As current encounters higher resistance, less current will flow for the same voltage.

Therefore, the correct answer encompasses both the consequence of a voltage drop and the decrease in current due to the presence of resistance in the circuit.