Example: If the refractivity N is such that:
M= 10 6 h a =400 MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHXgaruavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdi9qqqj=hEeeu0lXdbba9frFj0xb9Lqpepeea0xd9s8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr0=vr0db8meaabaGacmGadiWaaiWabiabciaafiaakeaacaWGnbGaeyypa0JaaeymaiaabcdadaahaaWcbeqaaiaabAdaaaGcdaWcaaqaaiaadIgaaeaacaWGHbaaaiabg2da9iaabsdacaqGWaGaaeimaaaa@42C6@
the refractive modulus is 400 M-units, or M = 400
Exemple: Si le coïndice N est tel que:
on peut dire: le module de réfraction est de 400 unités M, ou bien M = 400