Practice question

Given: What is the critical angle for a glass-air interface if the refractive index of glass is 1.52 ? These values define the system as per NCERT data. Formula: Critical angle: sin i_c = n_2/n_1. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Glass ( n_1 = 1.52 ), air ( n_2 = 1 ). sin i_c = 1/1.52 approx 0.658 . i_c = sin^{-1(0.658) approx 41.1° . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.