Practice question

**TIR application** requires n₁>n₂ and θ₁>C. Critical angle formula derived from Snell's law with θ₂=90°, n₁ sinC = n₂ sin90° = n₂, so sinC = n₂/n₁. For glass-air sinC=1/1.52, C≈41°, for water-air 48.6°, determining cutoff for transmission. For a concave mirror, a virtual and magnified image is formed when the object is placed between the focal point (F) and the pole (P). Here, the reflected rays diverge, and their backward extensions converge behind the mirror, producing a virtual, erect, and magnified image. Substituting values gives Object between focal point and pole, which matches expected image position and magnification from mirror/lens formula 1/f = 1/v -