Kng (光) sī pho-tn̂g (wavelength) ē-tit hō͘ ba̍k-chiu (eye) khoàⁿ--tio̍h ê tiān-chû-pho (electromagnetic radiation), khiā kóng khoàⁿ-ū-kng (visible light). Ah nā ki-su̍t-te̍k (technical) iah sī kho-ha̍k kóng ê kng, tō pau-hâm chhìn-chhái pho-tn̂g ê tiān-chû-pho.

Kng ū 3 chióng ki-pún sèng-chit:

  • kiông-tō͘ (intensity), iah sī pho-hok (amplitude), kap lán kám-kak--tio̍h ê kng-tō͘ (brightness) ū tī-tāi,
  • pîn-lu̍t (frequency), iah sī pho-tn̂g, lán khoàⁿ--tio̍h ê sek (color),
  • phian-kng (polarization), tō sī chùn-tāng ê kak-tō͘ (angle of vibration), phó͘-thong khoân-kéng sió-khoá ē-sái kám-kak--tio̍h ê Haidinger ê oē-pit (Haidinger's brush) chit ê hiān-siōng.

Bu̍t-chit (matter) ū pho-lia̍p jī-goân-sèng (wave-particle duality), kng kâng-sî ū pho kap lia̍p-chú 2 chióng sèng-chit tī--leh. Kng ê pún-chit sī hiān-tāi bu̍t-lí-ha̍k ê 1 ê koan-kiàn būn-tê.