# Angular Momentum of a Photon

*Most recent answer: 02/25/2012*

Q:

Take a photon, for instance. Is there a theoretical limit to its angular momentum?

- Bill H (age 55)

Michigan

- Bill H (age 55)

Michigan

A:

The intrinsic angular momentum of a photon is restricted to plus or minus one in Planck units, h-bar = 6.58×10

LeeH

In Lee's line of work they use units like eV-sec. For those with a more refined esthetic sense, the SI value is 1.05×10

^{−16}eV·sec. In addition it can carry angular momentum with respect to a fixed point given by its momentum, E/c, times its distance r. This latter angular momentum has no limit.LeeH

In Lee's line of work they use units like eV-sec. For those with a more refined esthetic sense, the SI value is 1.05×10

^{-34}J-s and the cgs value is 1.054 ×10^{-27}erg-s Mike W.*(published on 02/25/2012)*