A child is using a spectacle with power of -2.5 D. What is meant by the negative sign?

Explanation

To solve the question regarding the meaning of the negative sign in the power of a lens, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Lens Power**:
The power of a lens is defined as the ability of the lens to converge or diverge light rays. It is measured in diopters (D).

2. **Identifying the Sign of Power**:
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