What do you understand by snails low

1.	What do you understand by snails low
Answer» Laws of refraction of light(i) Incident ray, refracted ray and normal at the point of incidence all lie in the same plane.(ii) Ratio of sine of angle of incidence to the sine of angle of refraction is a constant quantity known as refractive index of the medium.{tex}\\mu=\\frac{\\sin\\;i}{\\sin\\;r}{/tex}

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