How long did it take for tv to spread around the world?

Answer 1

TV transmissions travel at the same speed light does. Because at least for broadcast tv it is transmitted as a special kind of light wave. So it would take only a few seconds.

My bad I think I answered the wrong question.

Answer 2

The television was a development that took several decades and the involvement of many people. Early developments with electricity lead to the invention of the thermionic valve, the basis for electronic systems and an integral part of radio systems.

An inventor, Paul Nipkow developed the Nipkow disc in the 1870s and patented it as a means to electronically transfer images. He never made use of the disc and the patent was allowed to lapse some years later.

It was a combination of radio systems and the Nipkow disc that gave John Logie Baird the tools to produce the worlds first working television in 1925. It was a project that took Baird more than a decade but the roots of his invention reach back half a century before he unveiled his "Televisor" to the public in London, England. So, we can say that it took Baird ten years or that it took the scientific community fifty years to invent the television.

Others were working on the same challenge. Philo Farnsworth in America unveiled his first model in 1928 and by 1929 had completed his first television that had no moving parts.

Baird had published the principles of television image capture, transmission and display. Farnsworth showed the benefits of a fully electronic system and together they opened the way for future development of television that we know today.