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I've posted the picture below from Introduction to Electrodynamics by Griffiths, 3rd edition. Is the phenomenon described talking about total internal reflection? Is it necessary for the incident angle to be equal to 90 degrees for total internal reflection to occur?

enter image description here

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No and no: this seems to be considering "external" reflection, where the incoming and reflected ray travel in the medium with the lower index of refraction (in the air in the driving example); total internal reflection occurs rather when the ray travels in the medium with the higher index, and grazing incidence is not required, only an incidence angle greater than what would be required to refract the transmitted ray to 90 degrees.

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