For normal adjustment, length of astronomical telescope is______________?
Correct answer: A. fo + fe
- A. fo + fe
- B. fo - fe
- C. fo / fe
- D. fe / fo
Explanation
In normal adjustment, the intermediate image formed by the objective lies at the focal point of the eyepiece, so the final image is at infinity. The distance between the lenses is therefore the sum of their focal lengths, L = fo + fe, where L, fo and fe are lengths. The likely mistake is choosing b, fo - fe, which applies a difference instead of the required separation sum.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
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.
Practise Optics
665 free Optics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 11 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Optics questions
Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?
Least distance of distinct vision_____________?
Image of an object 5 mm high is only 1 cm high. Magnification produced by lens is__________________?
Final image produced by a compound microscope is_____________?
In multimode step index fibre the refractive index of core and cladding is____________?
If a convex lens of large aperture fails to converge the light rays incident on it to a single point, it is said to suffer from______________?