Find the focal length of a lens having -0.5 D power.

Explanation

To find the focal length of a lens with a power of -0.5 D, we can use the relationship between power (P) and focal length (F) given by the formula:

\[ P = \frac{1}{F} \]

Where:
- \( P \) is the power of the lens in diopters (D)
- \( F \) is the focal length in meters (m)

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