I would like to say that there is no sharp division between one kind of wave and the next. The classification is based roughly on how the waves are produced and/or detected.So we can just loosely divide them based on their wavelength but without any strict range.

As far as you question is concerned 462nm can never be infrared because viable light has roughly range from 400nm to 700nm as the name suggests **_infrared ie.inferior to red_** that is it comes below red in usual em spectrum diagram.(Note that red light is at higher wavelength region in visible spectrum) so you lecturer had make a mistake (slip of toungue) may be wanted to say UV rays which may be of that wavelength.

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  [1]: https://i.sstatic.net/tcqtq.jpg