The first ideas for scanning and sequential transmission of picture information for TV were from France but Alexander Bain (a Scot) invented the fax machine in 1846 which involved scanning and sequential transmission. Nipkow (German) had the brilliant idea of a simple disc scanner and patented a full TV system in 1884. Campbell Swinton (A Scot) proposed electronic TV in 1908. Baird (A Scot) developed TV based on Nipkow's disc. EMI (UK) worked on electronic TV using Zworykin's (Russian working in the USA) camera tube.
Does the D-layer never reflect signals? It absorbs MF (medium wave.. AM band) signals during the day when it is highly ionised. At night the ionisation disappears (no solar radiation) and signals are reflected by the E-layer. Seems strange that the D-layer has a large effect only up to around 2 MHz and as far as I know never reflects any signals.
Maybe some physicists out there can eplain the mysteries of the various layers. D E and F1 and F2. Is it to do with density at different heights? Are there A and B layers? Why does the level of ionisation effect different frequencies so differently?. Normally signals don't get reflected about 30 MHz but at periods of high sunspot numbers low-VHF can be received over short wave like distance.. BBC TV from London on 45 MHz (now shut down) for instance being receieved in South Africa or Australia. And at times FM band and higher frequencies refelect off the E-layer (unrelated to sunspot max),,Sporadic E. One theory was that the later was caused by thunder storms.
I am radio engneer but know little about the physics involved.
4 out of 5 recent US Presidents have been left handers? Given that 1 in 10 of the population is left handed what is the probability of this? Say it was taking socks out of draw with the light off.. 1 White to 9 Black. What are chances of having 4 White and 1 Black.. I get 0.00045 ??
More accurately what is the probability that a continuous sequence of 5 presidents out of 43 has 4 left handers?
Mod edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate - thanks!