In which decade were the first successful diode and triode vacuum tubes invented?

A. 1800s

B. 1880s

C. 1890s

D. 1900s

Answer: Option D

Solution(By Examveda Team)

In 1904, John Ambrose Fleming invented the first practical electron tube called the 'Fleming Valve', which is a diode rectifier. In 1906, Lee de Forest invented the audion later called the triode, which provided signal amplification.