Physics
Total Internal Reflection
Critical Angle and Total Internal Reflection in a Prism
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⚡ Quick Summary
Total internal reflection occurs when light travels from a denser to a rarer medium at an angle greater than the critical angle. In a prism, the minimum refractive index required for total internal reflection to occur depends on the prism's geometry. The critical angle (θ_c) is related to the refractive index (μ) by sin(θ_c) = 1/μ.
['μ ≥ √2 (for total internal reflection in a specific prism configuration)', 'sin(θ_c) = 1/μ']
For a ray of light incident normally on one face of a right prism to emerge parallel to the incident direction after two total internal reflections, the refractive index (μ) of the prism must be greater than or equal to √2. The critical angle (θ_c) is given by sin⁻¹(1/μ). The angle of incidence at each surface where total internal reflection is desired must be greater than or equal to the critical angle.