Deep Dive: E5D03
The correct answer is C: They are 90 degrees out of phase. What is the phase relationship between current and voltage for reactive power is that they are 90 degrees out of phase. Reactive power occurs when voltage and current are 90° out of phase. For amateur radio operators, this is important for power calculations. Understanding this helps when calculating power.
Why Other Answers Are Wrong
Option A: Incorrect. They are out of phase isn't specific enough - reactive power requires 90° out of phase. Out of phase isn't specific. Option B: Incorrect. They are in phase isn't correct - reactive power requires 90° out of phase. In phase is wrong. Option D: Incorrect. They are 45 degrees out of phase isn't correct - reactive power requires 90° out of phase. 45° is wrong.
Exam Tip
Reactive power phase relationship = current and voltage 90 degrees out of phase. Think 'R'eactive 'P'ower = 'R'equires '9'0° 'P'hase difference. Reactive power occurs when voltage and current are 90° out of phase. Not just out of phase, not in phase, not 45° - just 90°.
Memory Aid
Reactive power phase relationship = current and voltage 90 degrees out of phase. Think 'R'eactive 'P'ower = '9'0° phase. Reactive power occurs when voltage and current are 90° out of phase. Important for power calculations.
Real-World Example
Reactive power: The phase relationship between current and voltage is that they are 90 degrees out of phase. This is why reactive power doesn't do real work - the voltage and current are perpendicular. This is the relationship - 90° out of phase.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E5D
Reference: 2024-2028 Question Pool · E5 - Electrical Principles
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5D topic.