Question

Who invented the thermionic valve?
(A) John Ambrose Fleming
(B) Owen Richardson
(C) Lee de Forest
(D) Philipp Lenard

Answer 1

Hint : Thermionic valve can be defined as the electronic device which consists of the system of the electrodes which are arranged in an evacuated glass.

Complete Step By Step Answer:
Thermionic valve or the tube uses the phenomenon of the thermionic emission of the electrons from the hot cathode which is used for the number of the fundamental electronic functions such as the signal amplification and the current rectification.
Thermionic valve was invented by John Ambrose Fleming.
John Ambrose Fleming was an English Electrical Engineer and physicist who was born on $29$ November, $1849$ in Lancaster and died in the year $1945$ in Sidmouth, Devon. He made numerous contributions in the field of electronics, photometry, electronic measurements and wireless telegraphy.
From the given multiple choices – the option A is the correct answer.

Note :
Always remember that thermionic valve is also known as the vacuum tube, thermionic vacuum tube, thermionic tube or the electron tube. Do not get confused with the same type of the terminologies it means the same.