Test Index

Communication System

Section: Physics

Question : 4 of 13

Marks: +1, -0

Solution:

f=1000\,\text{kHz}=1\times10^6\,\text{Hz}

Speed of electromagnetic wave in free space,

c=3\times10^8\,\text{m/s}

Step 2: Find the wavelength

\lambda=\frac{c}{f}=\frac{3\times10^8}{1\times10^6}=300\,\text{m}

Step 3: Relation between antenna length and wavelength

For efficient radiation, the minimum antenna length (usually a quarter-wave antenna) is:

L=\frac{\lambda}{4}

Step 4: Calculate

L

L=\frac{300}{4}=75\,\text{m}

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