Deep Dive: E5C07
The correct answer is D: On the horizontal axis. Where is the impedance of a pure resistance plotted on rectangular coordinates is on the horizontal axis. Pure resistance has no reactance, so it's on the real (horizontal) axis. For amateur radio operators, this is important for circuit theory. Understanding this helps when plotting impedances.
Why Other Answers Are Wrong
Option A: Incorrect. On vertical axis isn't correct - pure resistance is on horizontal axis. Vertical axis is wrong. Option B: Incorrect. On line through origin slanted at 45 degrees isn't correct - pure resistance is on horizontal axis. 45° line is wrong. Option C: Incorrect. On horizontal line offset vertically isn't correct - pure resistance is on horizontal axis at origin. Offset isn't correct.
Exam Tip
Pure resistance on rectangular coordinates = on horizontal axis. Think 'P'ure 'R'esistance = 'P'ositive 'R'eal axis (horizontal). Pure resistance has no reactance, so it's on the real (horizontal) axis. Not vertical, not 45°, not offset - just horizontal axis.
Memory Aid
Pure resistance on rectangular coordinates = on horizontal axis. Think 'P'ure 'R'esistance = 'H'orizontal axis. Pure resistance has no reactance, so it's on the real (horizontal) axis. Important for circuit theory.
Real-World Example
The impedance of a pure resistance plotted on rectangular coordinates: It's on the horizontal axis. Since pure resistance has no reactance (imaginary part = 0), it lies on the real axis, which is the horizontal axis. This is where it's plotted - on the horizontal axis.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E5C
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 E5C topic.