Question

Two values of spin quantum numbers i.e., $+1/2$ and $- 1/2$ represent

• A. up and down spin of the electrons respectively
• B. two quantum mechanical spin states which refer to the orientation of spin of the electron
• C. clockwise and anti-clockwise spin of the electrons respectively
• D. anti-clockwise and clockwise spin of the electrons respectively

Answer 1

Answer: (B)

Spin angular momentum of the electron, a vector quantity can have two orientations relative to the chosen axis. These two orientations take the values of $+1/2$ or $-1/2$ and are called two spin states of the electrons.