The body which absorbs all the light rays and no light rays is reflected back is called a perfectly black body. as it doesn't reflect the light and the light rays didn't reach our eyes, so it will be absolutely invisible.
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A perfectly black body is an idealized physical body that absorbs all incident electromangnetic radiation , regardless of frequency or angle of incidence. A white body is one with a rough surface that reflects all incident rays completely and uniformly in all directions.