MUF MCQs

Practice MUF MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1

Antenna & Wave PropagationMUF

The maximum usable frequency (MUF) for a given ionospheric path is generally?

AAt least as high as the relevant critical frequency and depends on path geometry
BAlways zero
CAlways lower than every critical frequency
DIndependent of ionosphere and path

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Correct Answer: A. At least as high as the relevant critical frequency and depends on path geometry

Explanation: For oblique incidence, frequencies above the vertical-incidence critical frequency may be returned; MUF depends on layer conditions and geometry.

Reference: Standard antenna and wave propagation: muf

Question 2

Antenna & Wave PropagationMUF

Under the simple flat-Earth secant-law approximation, MUF is related to critical frequency fc and incidence angle i measured from the vertical by?

AMUF = fc sec i
BMUF = fc cos i
CMUF = fc sin i
DMUF = fc tan i

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Correct Answer: A. MUF = fc sec i

Explanation: The secant law gives MUF≈fc sec i for idealized ionospheric propagation.

Reference: Standard antenna and wave propagation: muf

Question 3

Antenna & Wave PropagationMUF

If the critical frequency is 5 MHz and the secant of the incidence angle is 2, the approximate MUF is?

A2.5 MHz
B5 MHz
C10 MHz
D25 MHz

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Correct Answer: C. 10 MHz

Explanation: Using MUF=fc sec i gives 5×2=10 MHz.

Reference: Standard antenna and wave propagation: muf