N'ọnwa Machị afọ 1887, Planck lụrụ Marie Merck (1861<unk>1909), nwanne otu nwa akwụkwọ ibe ya, ma soro ya kwaga n'ụlọ a na-akwụ ụgwọ na Kiel. Ha mụrụ ụmụ anọ: Karl (1888<unk>1916), ụmụ ejima Emma (1889<unk>1919) na Grete (1889<unk>1917), na Erwin (1893<unk>1945). Ajụjụ: Ụmụ ole ka Planck na Merck nwere?
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