Question

The quantum numbers $+\frac{1}{2}$ and $-\frac{1}{2}$ for the electron spin represent

• A. Rotation of the electron in clockwise and anticlockwise direction respectively
• B. Rotation of the electron in anticlockwise and clockwise direction respectively
• C. Magnetic moment of the electron pointing up and down respectively
• D. Two quantum mechanical spin states which have no classical analogue

Answer 1

The correct option is D Two quantum mechanical spin states which have no classical analogue

An electron spins around its own axis, much in a similar way as earth spins around its own axis while revolving around the sun. In other words, an electron has, besides charge and mass, intrinsic spin angular quantum number. Spin angular momentum of the electron, can have two orientations relative to the chosen axis. These two orientations are distinguished by the spin quantum numbers which can take the values of +½ or –½.
Electron spin has no classical counterpart.