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.
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.