For a lens, the relationship between object distance, image distance and focal length is
Correct answer: A. 1 over f equals 1 over v plus 1 over u, with a sign convention applied
- A. 1 over f equals 1 over v plus 1 over u, with a sign convention applied
- B. f equals u plus v
- C. f equals uv
- D. 1 over f equals u plus v
Explanation
The lens formula relates the reciprocals rather than the quantities themselves, and a consistent sign convention is essential, with real distances and real images taken as positive in the usual convention. Magnification is the image distance divided by the object distance. Careless sign handling is the commonest source of wrong answers in lens problems.
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About Optics
Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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