The image of an object placed inside the focal length of a convex lens will be largest and clearest when it is at the:
Correct answer: B. Near point
- A. Less than 25 cm
- B. Near point
- C. Greater than 25 cm
- D. Infinity
Explanation
When an object is placed inside the focal length of a convex lens, a virtual, upright, and magnified image is formed on the same side of the lens as the object. The size and clarity of the image depend on the distance between the lens and the object. As the object is moved closer to the lens, the image becomes larger and more magnified. However, if the object is moved too close to the lens, the image becomes blurred and distorted. The distance at which the image is largest and clearest is called the "near point" or "least distance of distinct vision". For a normal eye, the near point is about 25 cm from the eye. Therefore, when an object is placed inside the focal length of a convex lens, the image will be largest and clearest when it is at the near point, which is about 25 cm from the eye. The image will be smaller and less clear if the object is placed closer or further away from the near point.
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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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