Explanation: Ohm's Law describes the fundamental relationship between voltage (E), current (I), and resistance (R) in an electrical circuit. The core formula states that voltage equals current multiplied by resistance: **E = I x R**. From this foundational equation, we can derive the other forms: * To find current (I), divide voltage (E) by resistance (R): **I = E / R**. This makes option A correct. * To find resistance (R), divide voltage (E) by current (I): **R = E / I**. This makes option D correct. * Option C, **E = I x R**, is the direct statement of Ohm's Law itself, so it's correct. Option B, **I = R / E**, is incorrect. It suggests that current is found by dividing resistance by voltage, which contradicts the direct proportionality between current and voltage, and inverse proportionality with resistance. Understanding these relationships is crucial for designing and troubleshooting amateur radio circuits.