Referring to V=IR, reducing the voltage by half will do what to the resistance?

Referring to V=IR, reducing the voltage by half will do what to the resistance?

• A. Decrease by half
• B. Double
• C. Remain the same
• D. Increase by half

Answer: (A)

In Ohm's law, resistance is a property of the component and does not change just because the applied voltage changes (for an ohmic device). V = IR means the current through the resistor is I = V/R. If you halve the voltage and the resistor stays the same, the current will also halve, but the resistance stays the same. For example, with V = 10 V and R = 5 Ω, the current is I = 10/5 = 2 A. Halve the voltage to 5 V, the current becomes I = 5/5 = 1 A, while R remains 5 Ω. So reducing the voltage by half alters the current, not the resistance.

In Ohm's law, resistance is a property of the component and does not change just because the applied voltage changes (for an ohmic device). V = IR means the current through the resistor is I = V/R. If you halve the voltage and the resistor stays the same, the current will also halve, but the resistance stays the same.

For example, with V = 10 V and R = 5 Ω, the current is I = 10/5 = 2 A. Halve the voltage to 5 V, the current becomes I = 5/5 = 1 A, while R remains 5 Ω. So reducing the voltage by half alters the current, not the resistance.