Lee De Forest is known for which achievement?

• A. Amplified sound using the Audion tube
• B. First wireless telephony voice transmission
• C. Transatlantic radio signal
• D. The phonograph invention

Answer: (A)

The important concept is how amplification of audio signals with vacuum-tube technology made radio practical. Lee De Forest popularized the Audion, a vacuum-tube amplifier that could boost weak electrical signals, allowing voices and music to be transmitted and heard clearly over radio systems. This breakthrough is why amplified sound using the Audion tube best captures his achievement—it gave radio its first real ability to amplify and reproduce audio. The other milestones belong to different pioneers: Reginald Fessenden is tied to the first wireless voice transmission, Marconi to the first transatlantic radio signal, and Edison to the phonograph.