The Standard Model prescribes a definite Lagrangian for the coupling of the W-boson to the photon. Measuring the coupling constant will test an important ingredient of the Model i.e., the verification of non-Abelian gauge structure of the Standard Model. Using the process eγ→ Wν we study the most general C and P conserving vertex in e + e - collisions at a future 500 GeV collider. This vertex contains two parameters, the anomalous magnetic moment κ and the quadrupole moment λ. For the process eγ→ Wν we present analytical expressions for the differential cross-section for arbitrary values of κ and λ which explicitly demonstrate the presence of a zero at u =0 in the Standard Model.