Using Ohm's law and P=VI, what is the current through a 25 Ω load when connected to a 5 V supply?

• A. 0.2 A
• B. 0.5 A
• C. 0.25 A
• D. 1 A

Answer: (A)

Current is set by I = V/R. With 5 V across a 25 Ω load, the current is 5 / 25 = 0.2 A. You can check with P = VI: P = V^2/R = 25/25 = 1 W, and then I = P/V = 1 / 5 = 0.2 A. So the current flowing is 0.2 A. Other numerical options would require different voltage or resistance.