UNDERSTANDING TOTAL INTERNALTotal internal reflection is a total reflection of a beam of light at the boundary of two mediums, when the angle of incidence in the optically denser medium exceeds a specific critical angle.Critical angle is the greatest angle of incidence where the refracted angle is 90 away from the normal line when the ray is travel from denser medium to a less dense medium. ( i.e. from glass to air ).Angle of incidence, iis increased to the critical angle, c ( i = c).Angle of refraction is 90.roduces a refracted ray that travel along glass!air boundary.When the angle of refraction in less dense is 90, Itangle of incident is dene as critical angleAngle of incidence, i is greater than critical angle, c( i >c )."orefraction occurs.All the light energy is reflected within the glass at the glass!air boundary.#otal internal reflection occurs.Relationship between Critical Angle, cand Refractive Index, nrinsinsin=cnsin90 sin0=cnsin1=$ncident ray, irefracted ray, rciiairglass, nsin 90 % &application