Find number abcIf c77bc - a050c = a7cb0 find number abc. Multiple solutions may exist.
Correct answers: 7
Fessenden wireless patentIn 1901, Prof. R. A. Fessenden applied for a U.S. patent for "Improvements in apparatus for the wireless transmission of electromagnetic wave, said improvements relating more especially to the transmission and reproduction of words or other audible signals." According to Important Events in Radiotelegraphy, a U.S. Dept of Commerce publication (1916), "It appears that in connection with this apparatus there was contemplated the use of an alternating current generator having a frequency of 50,000 per second." Prof. Fessenden was granted a number of United States patents between 1899 and 1905 covering devices used in connection with radiotelegraphy.