After World War II, two new competing formats came onto the market and gradually replaced the standard "78": the 33 13 rpm (often just referred to as the 33 rpm), and the 45 rpm (see above). The 33 13 rpm LP (for "long-play") format was developed by Columbia Records and marketed in June 1948. RCA Victor developed the 45 rpm format and marketed it in March 1949, each pursuing their own r&d in secret. Both types of new disc used narrower grooves, intended to be played with smaller stylustypically 0.001 inches (25 m) wide, compared to 0.003 inches (76 m) for a 78so the new records were sometimes called Microgroove. In the mid-1950s all record companies agreed to a common recording standard called RIAA equalization. Prior to the establishment of the standard each company used its own preferred standard, requiring discriminating listeners to use pre-amplifiers with multiple selectable equalization curves.
When did the 33 1/3 rpm hit the market?
June 1948

Madonna holds the record for the most number-ones on all combined Billboard charts, including twelve number-one songs on the Billboard Hot 100 and eight number-one albums on the Billboard 200. With 45 songs topping the Hot Dance Club Songs chart, Madonna became the artist with the most number-one songs on an active Billboard chart, pulling ahead of George Strait with 44 number-one songs on the Hot Country Songs chart. She has also scored 38 top-ten singles on the Hot 100, more than any other artist in history. In 2008, Billboard magazine ranked her at number two, behind The Beatles, on the Billboard Hot 100 All-Time Top Artists, making her the most successful solo artist in the history of American singles chart.
Who has the most number one songs in an active BiIlboard chart?
Madonna

Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight and enable solar energy to be harnessed at different levels around the world, mostly depending on distance from the equator. Although solar energy refers primarily to the use of solar radiation for practical ends, all renewable energies, other than geothermal and tidal, derive their energy from the Sun in a direct or indirect way.
How are solar technologies defined?
passive or active