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Assertion–Reason (Transmission Lines): A matched load has impedance equal to the line’s characteristic impedance because a matched termination absorbs all incident power without reflection.

Difficulty: Easy

Correct Answer: Both A and R are correct and R is correct explanation of A

Explanation:


Introduction / Context:
Matching in transmission lines eliminates reflections, maximizes power transfer, and ensures flat frequency response. Understanding why ZL = Z0 is fundamental in RF design.


Given Data / Assumptions:

  • Lossless or low-loss line with characteristic impedance Z0.
  • Load ZL can be chosen for matching.
  • Reflection coefficient Γ = (ZL − Z0) / (ZL + Z0).


Concept / Approach:
When ZL = Z0, Γ = 0 and no power is reflected; all incident power is absorbed (and ideally delivered to the load). The definition of a matched termination is precisely that it equals Z0 and thus absorbs all incident power, providing the causal link from the Reason to the Assertion.


Step-by-Step Solution:

Set ZL = Z0 ⇒ Γ = 0.VSWR = (1 + |Γ|) / (1 − |Γ|) = 1 (perfect match).No standing waves form; all incident power is delivered to the matched load.


Verification / Alternative check:
Time-domain view: a wave reaching a matched load sees no discontinuity and thus no reflection; frequency-domain view: the impedance transformation along the line terminates in Z0 with flat response.


Why Other Options Are Wrong:

If R stated were false or unrelated, we would not obtain Γ = 0 or VSWR = 1.Only the given Reason directly explains why the Assertion holds in standard line theory.


Common Pitfalls:

Confusing “maximum power transfer” Thevenin matching in lumped circuits with transmission-line matching; here, ZL must equal Z0 at the operating frequency.


Final Answer:

Both A and R are correct and R is correct explanation of A
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