Nā te mea kua taea e koe te tatau i te horopeta e whiwhi ana koe, me mōhio koe ki te horopeta e tino whai hua ana. Ko te nuinga o ngā tuhinga arotake me ngā rauemi mātauranga e kī ana he pai te horopeta i waenga i te 0.1J/cm² ki te 6J/cm² mō ngā pūtau, ā, ki te iti ake te kore mahi, ka nui ake te whakakore i ngā painga.
Heoi, i kitea e ētahi rangahau he hua pai i roto i ngā awhe teitei ake, pērā i te 20J/cm², 70J/cm², tae atu ki te 700J/cm². Tērā pea ka kitea he pānga hohonu ake o te pūnaha i ngā horopeta teitei ake, i runga i te nui o te pūngao e whakamahia ana ki te tinana. Tērā pea he whai hua te horopeta teitei ake nā te mea ka hohonu ake te uru o te mārama. He hēkona noa iho te roa o te whiwhi i te horopeta o te 1J/cm² ki te paparanga o runga o te kiri. Tērā pea ka 1000 ngā wā ka roa ake te whiwhi i te horopeta o te 1J/cm² ki roto i te kiko uaua hohonu, me 1000J/cm²+ te roa ki te kiri o runga.
He mea tino nui te tawhiti o te pūtake mārama i konei, nā te mea ka whakatau i te kaha o te mārama e pā ana ki te kiri. Hei tauira, mā te whakamahi i te Pūrere Rama Whero i te 25cm hei utu mō te 10cm ka roa ake te wā paninga e hiahiatia ana engari ka kapi i te wāhi kiri nui ake. Kāore he he o te whakamahi mai i tawhiti atu, engari kia tino whakaea mā te whakanui ake i te wā paninga.
Te tatau i te roa o te wātū
Me mōhio koe ki te kaha o tō rama (e rerekē ana i runga i te tawhiti) me te horopeta e hiahiatia ana e koe. Whakamahia te tātai i raro nei hei tatau i te maha o ngā hēkona e hiahiatia ana hei whakamahi i tō rama:
Wā = Horomanga ÷ (Kiato Mana x 0.001)
Te wā i roto i ngā hēkona, te horopeta i roto i te J/cm² me te mātotoru mana i roto i te mW/cm²