Practice question

**Refractive index** n = c/v, water 1.33 means light 1.33 times slower than vacuum. Passing from water to air at 49°, n₁ sinθ₁ =1.33×sin49°≈1.33×0.755=1.004>1, so sinθ₂>1 impossible, total internal reflection occurs, no refraction. A convex lens exhibits chromatic aberration with white light because different wavelengths refract by varying amounts due to the lens’s material having a wavelength-dependent refractive index. This causes colored fringes as focal points differ for each color, blurring the image. Substituting values gives Due to chromatic aberration, which matches expected image position and magnification from mirror/lens formula 1/f = 1/v - 1/u (lens) or 1/f = 1/v + 1/u (mirror), confirming sign conventions and refraction principles.