If the length of a telescope is 96 cm, the focal lengths of its lenses are:
Correct answer: C. 90 cm, -6 cm
- A. 100 cm, -4 cm:
- B. -80 cm, -6 cm:
- C. 90 cm, -6 cm
- D. 90 cm, 6 cm:
Explanation
Explanation: The focal length of the telescope objective lens is positive, and that of the eyepiece is negative. In the context of the telescope, the combination of the positive focal length of the objective lens (or mirror) and the negative focal length of the eyepiece allows the telescope to form a real, inverted image produced by the objective, which is then magnified and observed through the eyepiece as a virtual, upright image. This configuration helps create a telescope system with desired characteristics for astronomical observation.
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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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