lens formula

Question

Thin lens formula relates object distance u, image distance v, focal length f as?

RankGuru · Accepted Answer

1. **Thin Lens Formula**: This fundamental equation relates the principal parameters of a lens in the paraxial approximation.
2. **Standard Form**: **$\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$**.
3. **Variables**:
   - $u$: Object distance (usually negative by convention).
   - $v$: Image distance.
   - $f$: Focal length (positive for convex, negative for concave).
4. **Difference from Mirror**: Note the negative sign between the reciprocals, unlike the mirror formula which uses a plus sign.
5. **Sign Convention**: Cartesian sign convention is essential for correctly applying this formula in problems.

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lens formula

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