A light ray falls at normal incidence on an equilateral prism, complete the path of the ray until it leaves the prism in the external environment. Say from which face (1, 2 or 3) the ray comes out and give the angle of refraction in the external medium, the index of refraction of the prism is 1.5.The prism is immersed in water. (n=4/3=1.33)The prism is in the air (n=1)

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