The phenomenon by which the apparent position of a star near the horizon appears slightly higher than its actual position is called

1. Your syllabus: the Earth's atmosphere has a refractive index that decreases with altitude (denser near the surface, rarer above). 2. Starlight passing from rarer to denser layers BENDS CONTINUOUSLY toward the normal as it descends. 3. By the time it reaches an observer's eye, the apparent direction is slightly HIGHER than the true direction (the eye traces back the final ray's apparent origin). 4. Consequence: stars near the horizon appear elevated; the sun appears above the horizon for several minutes BEFORE actual sunrise and AFTER actual sunset. 5. This is ATMOSPHERIC REFRACTION — distinct from other phenomena. 6. Options B (dispersion) gives the rainbow. Option C (diffraction) is a wave effect — different cause. Option D (scattering) gives blue sky and red sunsets, not apparent position shift. _Source: syllabus Physics Part 2, Ch 9, §9.5 (Refraction at Atmosphere), p. 8._