A coin at the bottom of a bucket filled with water appears raised. This phenomenon is due to:
Correct: C
When light rays from the coin travel from water (a denser medium) to air (a rarer medium), they bend away from the normal as they exit the water surface. When these diverged rays reach the observer's eye, the brain traces them back in straight lines, making the coin appear to be at a shallower, raised position. This bending of light is known as refraction.