Direct application of Ohm’s law: determine the source voltage required to drive 2 A through a 36 Ω resistor (show all steps clearly).

Introduction / Context:
Finding the voltage for a given current through a known resistance is the most common use of Ohm’s law. This calculation is foundational in power sizing, source selection, and safety checks for resistive loads.

Given Data / Assumptions:

• I = 2 A (current).
• R = 36 Ω (resistance).
• We assume an ideal source and purely resistive load.

Concept / Approach:

Use V = I * R. Multiply the given current by the resistance to get the required voltage. Verify the power as a sanity check.

Step-by-Step Solution:

Verification / Alternative check:

Rearrange Ohm’s law: I = V / R → V = I * R, which we used correctly. Units: amperes * ohms = volts.

Why Other Options Are Wrong:

1.8 V and 7.2 V are an order of magnitude too small; 18 V corresponds to 0.5 A through 36 Ω, not 2 A.

Common Pitfalls:

Accidentally dividing instead of multiplying; misreading units; ignoring that doubling current doubles voltage for a fixed resistance.

Final Answer:

72 V