1．Radio Frequency circuit is mainly used for? （ ）.
A． Processing audio signals
B． Wireless communication
C． Generate sine waves
D． Supply power
Answer: B． Wireless communication
Humankind communicates with artificially created radio waves that oscillate at various chosen frequencies. RF communication is used in many industries including television broadcasting, radar systems, computer and mobile platform networks, remote control, remote metering/monitoring, and many more.