Martin Hans Christian Knudsen (15.02.1871— 27.05.1949) was a Danish physicist and oceanographer, a member of the Royal Danish Academy of Sciences and Letters (1909) and its secretary in 1917—46.
Boris Pavlovich Konstantinov (6.07.1910 —9.07.1969) was a Soviet physicist, an academician (1960; corresponding member 1953) and vice-president of the USSR Academy of Sciences (from 1967).
Daulat Singh Kothari (born 6.07.1906) is an Indian physicist and astrophysicist and a member of the Indian Academy of Sciences, and was its president (1973 — 75).
Andrei Kapitonovich Krasin (21.05.1911—28.03.1981) was a Soviet physicist and an academician of the Academy of Sciences of the Byelorussian SSR (1960).