Lens Formula
Mediumphysics
Thin lens formula relates object distance u, image distance v, focal length f as?
Select the correct option:
Solution
Incorrect! Answer:
1/f = 1/v - 1/u
- Thin Lens Formula: This fundamental equation relates the principal parameters of a lens in the paraxial approximation.
- Standard Form: v1−u1=f1.
- Variables:
- u: Object distance (usually negative by convention).
- v: Image distance.
- f: Focal length (positive for convex, negative for concave).
- Difference from Mirror: Note the negative sign between the reciprocals, unlike the mirror formula which uses a plus sign.
- Sign Convention: Cartesian sign convention is essential for correctly applying this formula in problems.
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About This Question
- Subject
- physics
- Chapter
- optics
- Topic
- lens formula
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
1/f = 1/v - 1/u
- Thin Lens Formula: This fundamental equation relates the principal parameters of a lens in the paraxial approximation.
- Standard Form: v1−u1=f1.
- Variables:
- u: Object distance (usually negative by convention).
- v: Image distance.
- f: Focal length (positive for convex, negative for concave).
- Difference from Mirror: Note the negative sign between the reciprocals, unlike the mirror formula which uses a plus sign.
- Sign Convention: Cartesian sign convention is essential for correctly applying this formula in problems.
This medium difficulty physics question is from the chapter optics, covering the topic of lens formula. It appeared in the 2025 exam.
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