Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E5B
E5B03E5B

How is impedance in polar form converted to an equivalent admittance?

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Deep Dive: E5B03

The correct answer is B: Take the reciprocal of the magnitude and change the sign of the angle. How is impedance in polar form converted to an equivalent admittance is to take the reciprocal of the magnitude and change the sign of the angle. Admittance is the reciprocal of impedance, so magnitude is reciprocal and angle sign changes. For amateur radio operators, this is important for circuit calculations. Understanding this helps when converting between impedance and admittance.

Why Other Answers Are Wrong

Option A: Incorrect. Reciprocal of angle and change sign of magnitude isn't correct - reciprocal of magnitude and change sign of angle is correct. Angle/magnitude swap is wrong. Option C: Incorrect. Square root of magnitude and add 180 degrees to angle isn't correct - reciprocal of magnitude and change sign of angle is correct. Square root/180° isn't correct. Option D: Incorrect. Square magnitude and subtract 90 degrees from angle isn't correct - reciprocal of magnitude and change sign of angle is correct. Square/90° isn't correct.

Exam Tip

Impedance to admittance conversion = reciprocal of magnitude, change sign of angle. Think 'I'mpedance to 'A'dmittance = 'I'nvert 'A'mplitude, 'A'lter angle sign. Admittance is reciprocal of impedance. Not angle/magnitude swap, not square root/180°, not square/90° - just reciprocal magnitude, change angle sign.

Memory Aid

Impedance to admittance conversion = reciprocal of magnitude, change sign of angle. Think 'I'mpedance to 'A'dmittance = 'R'eciprocal, 'S'ign change. Admittance is reciprocal of impedance. Important for circuit calculations.

Real-World Example

Converting impedance in polar form to equivalent admittance: Take the reciprocal of the magnitude and change the sign of the angle. For example, if Z = 50∠30°, then Y = (1/50)∠-30° = 0.02∠-30°. This is the conversion - reciprocal magnitude, change angle sign.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E5B

Reference: 2024-2028 Question Pool · E5 - Electrical Principles

Key Concepts

Impedance in polar form Converted to equivalent admittance Reciprocal of magnitude Change sign of angle

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5B topic.