There no refraction for the incidence angleEg. According to snells lawLet the light pass from air to waterRef. Index of water=1. 33Ref. Index of air=1now according to snells lawN1 sinx1=N2 sinx2here x1=0 there for...N2 sinx2=0 N2 is not equal to 0 there for sinx2 is zero there for x2 is zero so ther refracted ray remains undeviated