Question

व्हाट इज द मीन फीचर ऑफ़ समर फील्ड थिअरी​

Answer 1

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According to Sommerfeld, the stationary orbits in which electrons are revolving around the nucleus in an atom are not circular but elliptical in shape. It is due to the influence of the centrally located nucleus. The electron revolves in elliptical path with nucleus at one of its foci.