The Nobel Prize in Physics 1924 was awarded to Karl Manne Georg Siegbahn "for his discoveries and research in the field of X-ray spectroscopy."
Manne Siegbahn received his Nobel Prize one year later, in 1925. During the selection process in 1924, the Nobel Committee for Physics decided that none of the year's nominations met the criteria as outlined in the will of Alfred Nobel. According to the Nobel Foundation's statutes, the Nobel Prize can in such a case be reserved until the following year, and this statute was then applied. Manne Siegbahn therefore received his Nobel Prize for 1924 one year later, in 1925.