AP EAMCET · PHYSICS · Communication System
The minimum size of an antenna for transmitting electromagnetic waves at \(1500 \mathrm{MHz}\) is
- A \(2 \mathrm{~cm}\)
- B \(5 \mathrm{~cm}\)
- C \(2 \mathrm{~m}\)
- D \(200 \mathrm{~cm}\)
Answer & Solution
Correct Answer
(B) \(5 \mathrm{~cm}\)
Step-by-step Solution
Detailed explanation
Minimum size of transmitting antenna, \(\begin{aligned} l & =\frac{\lambda}{4}=\frac{c / f}{4} \\ \Rightarrow l & =\frac{3 \times 10^8}{4 \times 1500 \times 10^6}=\frac{3 \times 25}{1500}=\frac{1}{20} \mathrm{~m} \\ & =\frac{100}{20} \mathrm{~cm}=5 \mathrm{~cm} \end{aligned}\)
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