Difficulty: Easy
Correct Answer: 100 Ω
Explanation:
Introduction / Context:For a lossless (or low-loss) transmission line, the characteristic impedance Z0 depends on its per-unit-length inductance L and capacitance C.
Given Data / Assumptions:
Concept / Approach:
For a lossless line, Z0 = sqrt(L / C). We will compute this directly using the given values.
Step-by-Step Solution:
1) Form the ratio L / C = (500 × 10^-9) / (50 × 10^-12) = (500/50) × 10^3 = 10 × 10^3 = 10^4.2) Take square root: Z0 = sqrt(10^4) = 100 Ω.3) Therefore, the characteristic impedance is 100 ohms.Verification / Alternative check:
Dimensional check: sqrt(H/F) has units of ohms. Numerical value agrees with typical coax impedances when L/C ratio is 10^4.
Why Other Options Are Wrong:
500 Ω, 250 Ω, 50 Ω, and 75 Ω do not satisfy Z0 = sqrt(L/C) for the supplied numbers.
Common Pitfalls:
Arithmetic slips with scientific notation; forgetting that Z0 depends on the ratio L/C, not on frequency for the ideal lossless case.
Final Answer:
100 Ω.
Discussion & Comments