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Question
In a certain murder investigation, it was important to discover whether the victim was long-sighted or short-sighted. How could a detective decide by examining his spectacles?
Solution
(a) If the victim's spectacles are fitted with convex lens, the detective can conclude that the victim was long-sighted. A person suffering from long-sightedness, or hypermetropia, wears spectacles with convex lenses to correct the defect.
(b) If the victim's spectacles are fitted with concave lens, the detective can conclude that the victim was short-sighted. A person with short-sightedness, or myopia, wears spectacles with concave lenses to correct the defect.
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