Question 6A441

Power (P) is the rate at which energy is consumed, transferred, or radiated. The fundamental formula relating power to current (I) and resistance (R) is derived from Ohm's Law (E = I * R, where E is voltage) and the basic power formula (P = E * I). By substituting E in the power formula with I * R, we get P = (I * R) * I, which simplifies to **P = I²R**. This formula directly calculates power given the current flowing through a resistance, making it ideal for determining power at the base of an antenna where current and feedpoint resistance are known. Option A, P = watts x amps, is dimensionally incorrect; power is measured in watts, and multiplying watts by amps does not yield power. Option C, P = current x resistance (P = I * R), is actually the formula for voltage (E = I * R) according to Ohm's Law, not power. Therefore, B is the only correct power formula in this context.