lˈɔː ʌv tˈoʊɾəl pɹˌɑːbəbˈɪlᵻɾi ɹᵻkwˈaɪɚz ðˈæt , wˌɪtʃ ɪn wˈʌn dᵻmˈɛnʃən ɹᵻdˈuːsᵻz tə ðə fˈækt ðætðə sˈʌm ʌvðə tɹænsmˈɪɾᵻd ænd ɹᵻflˈɛktᵻd kˈɜːɹənts ɪz ˈiːkwəl ɪn mˈæɡnɪtˌuːd tə ðɪ ˈɪnsɪdənt kˈɜːɹənt.
Law of total probability requires that , which in one dimension reduces to the fact that the sum of the transmitted and reflected currents is equal in magnitude to the incident current.