A wire has a resistance of 4 ohms and carries a current of 3 A. What is the voltage across the wire?
Correct: D
The voltage across the wire can be calculated using Ohm's law, V = IR, where V is the voltage, I is the current, and R is the resistance. Given I = 3 A and R = 4 ohms, we can calculate V = 3 * 4 = 12 V.