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  • CQ Amateur Radio

    OUR READERS SAY…

    Aug 01, 2020 5 minutes

    Violet is Not Red

    The following letter was directed to “Math’s Notes” editor Irwin Math, WA2NDM:

    Hi Irwin,

    I am a retired senior optical engineer, electro-optics physicist and was working with HeNe lasers. The wavelength was 632.8nm which translates to 474 terahertz (THz), so your statement that 484 terahertz is violet is wrong; that is in the red light frequency range.

    Longer wavelength equals lower frequency and shorter wavelength equals higher frequency. Or …

    Lower = Longer/Higher = Shorter (LLHS)

    My calculations are that

    Wavelength = frequency

    700 nm = 429 THz, and

    400 nm = 750 THz.

    – 73 de Phil Karras, KE3FL

    WA2NDM responds:

    Hello Phil,

    Thank you for your comments. Sometimes I work a little too fast. In the future I will be

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