A converging lens of focal length f is placed just above a water surface parallel to the surface without touching it. A point source of light S is placed inside the water vertically before the lens at a depth f from it. This arrangement will produce:
Correct answer: C. A virtual image of S in water
- A. A parallel beam of light converging from the lens
- B. A real image of S in air
- C. A virtual image of S in water
- D. A virtual image of S in air
Explanation
When light passes from water to air, it bends away from the normal, causing the light rays to converge differently. This results in the formation of a virtual image of the point source inside the water medium. The other options are incorrect because they do not consider the refraction at the water-air interface and the specific location of the image.
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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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