The magnifying power of a compound microscope increases when:
Correct answer: C. The focal length of the eye lens is increased, and that of the objective lens is decreased
- A. The focal length of the objective lens is increased, and the eye lens is decreased:
- B. Focal lengths of both objective and eyepiece are increased:
- C. The focal length of the eye lens is increased, and that of the objective lens is decreased
- D. Focal lengths of both objective and eyepiece are decreased:
Explanation
Explanation: The magnifying power (M) of a compound microscope is given by M = (1 + D/f) × (1 + D/fe), where D is the least distance of distinct vision, f is the focal length of the objective lens, and fe is the focal length of the eyepiece. To increase the magnifying power, it is beneficial to increase the focal length of the eyepiece (fe) and decrease the focal length of the objective lens (f).
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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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