Unit zph
Name zeptophot
Category Illuminance
Details A zeptophot (zph) is a unit of illuminance in the field of photometry, which is the science of measuring and quantifying the visible light in a given area. Illuminance is a measure of how much luminous flux (the visible light power) is incident on a surface per unit area.

The term "zepto" is a prefix used in the International System of Units (SI) to denote a factor of 10^-21, which is one sextillionth (0.000000000000000000001). Therefore, one zeptophot (zph) is equal to 10^-21 phot or 0.000000000000000000001 phot.

A phot (ph) is a non-SI unit of illuminance, equivalent to 10,000 lux (lx) in SI units, where lux is the unit of illuminance representing one lumen per square meter (lm/m²). Thus, one zeptophot (zph) is equal to 10^-21 phot, or 10^-17 lux (lx).

In practice, the zeptophot unit is almost never used, as it represents an extremely small quantity of light that would be imperceptible and negligible for most applications. Instead, more common units like lux (lx) or foot-candles (fc) are used to measure illuminance in real-world situations.
zph(zeptophot) to alx(attolux)zph(zeptophot) to aph(attophot)zph(zeptophot) to clx(centilux)zph(zeptophot) to cph(centiphot)zph(zeptophot) to dalx(decalux)zph(zeptophot) to daph(decaphot)zph(zeptophot) to dlx(decilux)zph(zeptophot) to dph(deciphot)zph(zeptophot) to Elx(exalux)zph(zeptophot) to Eph(exaphot)zph(zeptophot) to fc(foot-candle)zph(zeptophot) to flx(femtolux)zph(zeptophot) to fph(femtophot)zph(zeptophot) to Glx(gigalux)zph(zeptophot) to Gph(gigaphot)zph(zeptophot) to hlx(hectolux)zph(zeptophot) to hph(hectophot)zph(zeptophot) to klx(kilolux)zph(zeptophot) to kph(kilophot)zph(zeptophot) to lm/am²(lumen per square attometre)zph(zeptophot) to lm/cm²(lumen per square centimetre)zph(zeptophot) to lm/dam²(lumen per square decametre)zph(zeptophot) to lm/dm²(lumen per square decimetre)zph(zeptophot) to lm/Em²(lumen per square exametre)zph(zeptophot) to lm/fm²(lumen per square femtometre)zph(zeptophot) to lm/ft²(lumen per square foot)zph(zeptophot) to lm/Gm²(lumen per square gigametre)zph(zeptophot) to lm/hm²(lumen per square hectometre)zph(zeptophot) to lm/in²(lumen per square inch)zph(zeptophot) to lm/km²(lumen per square kilometre)zph(zeptophot) to lm/Mm²(lumen per square megametre)zph(zeptophot) to lm/mm²(lumen per square millimetre)zph(zeptophot) to lm/m²(lumen per square metre)zph(zeptophot) to lm/nm²(lumen per square nanometre)zph(zeptophot) to lm/Pm²(lumen per square petametre)zph(zeptophot) to lm/pm²(lumen per square picometre)zph(zeptophot) to lm/Tm²(lumen per square terametre)zph(zeptophot) to lm/ym²(lumen per square yoctometre)zph(zeptophot) to lm/Ym²(lumen per square yottametre)zph(zeptophot) to lm/zm²(lumen per square zeptometre)zph(zeptophot) to lm/Zm²(lumen per square zettametre)zph(zeptophot) to lm/µm²(lumen per square micrometre)zph(zeptophot) to lx(lux)zph(zeptophot) to Mlx(megalux)zph(zeptophot) to mlx(millilux)zph(zeptophot) to Mph(megaphot)zph(zeptophot) to mph(milliphot)zph(zeptophot) to nlx(nanolux)zph(zeptophot) to nph(nanophot)zph(zeptophot) to nx(nox)zph(zeptophot) to ph(phot)zph(zeptophot) to Plx(petalux)zph(zeptophot) to plx(picolux)zph(zeptophot) to Pph(petaphot)zph(zeptophot) to pph(picophot)zph(zeptophot) to Tlx(teralux)zph(zeptophot) to Tph(teraphot)zph(zeptophot) to ylx(yoctolux)zph(zeptophot) to Ylx(yottalux)zph(zeptophot) to yph(yoctophot)zph(zeptophot) to Yph(yottaphot)zph(zeptophot) to zlx(zeptolux)zph(zeptophot) to Zlx(zettalux)zph(zeptophot) to Zph(zettaphot)zph(zeptophot) to µlx(microlux)zph(zeptophot) to µph(microphot)