A 14 year old student is not able to see clearly the questions written of the black board placed at a distance of 5 m from him.
Name two possible cause of this defect.

Explanation

To solve the question regarding the 14-year-old student who cannot see clearly the questions written on a blackboard placed at a distance of 5 meters, we need to identify two possible causes of this visual defect.

### Step-by-Step Solution:

1. **Identify the Condition**:
The student is unable to see objects clearly at a distance, which suggests that he may be suffering from a condition known as myopia (nearsightedness). In myopia, distant objects appear blurry while close objects can be seen clearly.

**Hint**: Myopia is a common refractive error where distant objects are not focused on the retina.
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