In the Sommerfeld's modification of Bohr's theory, the trajectory of an electron in a hydrogen atom is

Options

A. A perfect ellipse
B. A closed ellipse like curve, narrower at the perihelion position and flatter at the aphelion position
C. A closed loop on a spherical surface
D. A rosette

Answer

C

Explanation

A closed loop on a spherical surface electron moves in a 3-d space, not in a 2d surface.