Question

A student sitting in the back row has difficulty seeing the blackboard. What kind of defect might the student's eye have? How can it be corrected?

Hint:

Myopia (short-sightedness) = near is clear, distant is blurry = use concave lens.
Hypermetropia (long-sightedness) = distant is clear, near is blurry = use convex lens.

Answer 1

Step 1: Understanding the Concept:
If a person can see nearby objects clearly but struggles to see distant objects (like a blackboard from the back row), they suffer from near-sightedness.

Step 2: Detailed Explanation:
This defect is known scientifically as Myopia.
In a myopic eye, the image of a distant object is formed in front of the retina instead of on it, often because the eyeball is too long or the lens is too curved.
To correct this, a diverging lens is needed to spread the light rays slightly before they enter the eye, allowing the eye's lens to focus them perfectly on the retina.

Step 3: Final Answer:
The defect is Myopia, and it is corrected by wearing spectacles containing concave lenses of suitable power.