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Communication — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsCommunication1 Mark
MCQ
Maximum useable frequency (MUF) in $F$-region layer is $x$, when the critical frequency is $60 \mathrm{MHz}$ and the angle of incidence is $70^{\circ}$. Then $x$ is
  • A
    $150 \mathrm{MHz}$
  • B
    $170 \mathrm{MHz}$
  • ✓
    $175 \mathrm{MHz}$
  • D
    $190 \mathrm{MHz}$
✓

Answer

Correct option: C.
$175 \mathrm{MHz}$
$M U F=\frac{f_c}{\cos \theta}=\frac{60}{\cos 70^{\circ}}=175 \mathrm{MHz}$

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