What should be the length of a half wave dipole antenna required to transmit audio frequency signals?
What should be the length of a half wave dipole antenna required to transmit audio frequency signals?
A. a.5 km
B. b.10 km
C. c.15 m
D. d.7.5 km
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Correct Answer - D
Audio signals have a frequency range of 20 Hz to 20 KHz `=20xx10^3` Hz
`therefore f=20 xx 10^3` Hz
The corresponding wavelength `lambda=c/f=(3xx10^8)/(20xx10^3)=(300xx10^6)/(20xx10^3) = 15xx10^3` m = 15 km
`therefore` Length of the antenna =`lambda/2` = 7.5 km
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