Subelement E: Antenna Systems- 5 Key Topics – 5 Exam Questions— Topic 40: Transmission Lines
Question 8-40E2
Element 8 (RADAR)The impedance total (ZO) of a transmission line can be calculated by ZO = √L/C when L and C are known. When a section of transmission line contains 250 microhenries of L and 1000 picofarads of C, its impedance total (ZO) will be:
Explanation
The characteristic impedance (ZO) of a transmission line is a fundamental property determined by the physical geometry and dielectric material between its conductors. For a lossless line, it's defined by the square root of the ratio of its distributed inductance (L) to its distributed capacitance (C).
To calculate ZO:
1. Convert the given values to standard units:
* L = 250 microhenries = 250 × 10⁻⁶ H
* C = 1000 picofarads = 1000 × 10⁻¹² F = 1 × 10⁻⁹ F
2. Apply the formula ZO = √L/C:
* ZO = √( (250 × 10⁻⁶ H) / (1 × 10⁻⁹ F) )
* ZO = √( 250 × 10³ )
* ZO = √250,000
* ZO = 500 ohms
Therefore, the impedance total (ZO) is 500 ohms. Options A, B, and D are incorrect as they do not result from the correct application of the formula with proper unit conversions.
Related Questions
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