Prism dispersion occurs because: MCQ with Answer and Explanation

Dispersion: n varies with λ (Cauchy's law), causing different refraction angles for colors. Frequency constant across media; wavelength changes. Memory aid: 'n(λ) ⇒ v(λ) ⇒ different bending; violet bends most'. Conceptual question testing dispersion mechanism, frequently examined in competitive optics sections.