Before telephones were created in 1876, men and women would send letter to communicate. Another way was in person. Only big companies could telegraph machine which they communicated trhough Morse Code.
High-frequency current is an alternating current that can be adjusted to different voltages to produce heat and is also known as ''Violet ray''.
Early in the 20th century, the Violet Ray was hailed as a significant advancement in the field of electrotherapy. The high-frequency gadget known as the Violet Ray was one of these electrotherapy treatments that was well-known a century ago. Martin offers his opinion on Nickola Tesla, who changed the primary current into high-frequency discharges while retaining parts of its original characteristics.
It ceased to exert the same force through the same motor, to sear and burn in its path, and to shock the muscles with a fatal and paralyzing jolt when in contact with it. When in use, high-frequency currents connected to a vacuum tube "electrode" produced a violet light. That is why is known as violet rays.
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The answer is (a). your welcome
