What happens when resistance is increased in a circuit?

What happens when resistance is increased in a circuit?

• A. Current is decreased
• B. Current increases
• C. Voltage decreases
• D. Power increases

Answer: (D)

When resistance changes, the power dissipated by a resistor depends on how the circuit is driven. If the current is held constant (a constant-current source), the power is P = I^2 R. With the current fixed, increasing the resistance makes the voltage across the resistor larger (V = I R), and since power is also V × I, a larger voltage with the same current means more power is dissipated. So, in a current-source setup, increasing resistance increases power. If instead the circuit is powered by a fixed voltage, increasing resistance reduces current (I = V/R), and power becomes P = V^2 / R, which decreases as resistance rises. The given answer assumes the constant-current scenario, where higher resistance means higher power.

When resistance changes, the power dissipated by a resistor depends on how the circuit is driven. If the current is held constant (a constant-current source), the power is P = I^2 R. With the current fixed, increasing the resistance makes the voltage across the resistor larger (V = I R), and since power is also V × I, a larger voltage with the same current means more power is dissipated. So, in a current-source setup, increasing resistance increases power.

If instead the circuit is powered by a fixed voltage, increasing resistance reduces current (I = V/R), and power becomes P = V^2 / R, which decreases as resistance rises. The given answer assumes the constant-current scenario, where higher resistance means higher power.