A thin rod of length f/3 lies along the axis of a concave mirror of focal length f. One end of its magnified image touches an end of the rod. The length of the image is:
Correct answer: B. 1/2f
- A. f
- B. 1/2f
- C. 2f
- D. 1/4f
Explanation
When one end of the rod touches the magnified image, it is located at the center of curvature. By applying the lens formula and calculations, we find that the length of the image is f/2.Option A (f) is incorrect as it does not consider the specific positioning of the image and rod. Option C (2f) is incorrect as it miscalculates the length of the image. Option D (1/4f) is incorrect as it does not account for the relationship between the focal length and positioning of the image.
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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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