Question

The length of the antenna required for the transmission of frequencies of EM waves with bandwidth having AF range is

• A. 15 km
• B. 1500 m
• C. 375 m
• D. 3.75 km

Answer 1

The correct option is D 3.75 km

The maximum audio frequency is given as 20000 Hz.
The length of the antenna is of the order of quarter wavelength or
$\frac{\lambda }{4}=\frac{c}{4\nu }=\frac{3\times {10}^5}{4\times 20000}=3.75km$