Why is the focal length of the objective lens longer than that of the eye piece lens in a telescope?

Why is the focal length of the objective lens longer than that of the eye piece lens in a telescope?

Telescope is meant to see the distant objects, so objective lens has to be of greater focal length to gather more light.

Why we keep focal length of eye lens is more than the focal length of objective lens in compound microscopes?

The compound microscope is used to observe an object which is very small. Hence, the focal lengths of objective lens and eyepiece in compound microscopes are decreased for more magnification but the focal length of the eyepiece lens is kept more than the focal length of objective lens.

How are the eyepiece and objectives similar?

Eyepieces and objectives both have magnification that each contribute to the overall system magnification. Magnification is usually denoted by an X next to a numeric value.

Why the objective lens of the small focal length is preferred in microscope?

A lens with a shorter focal length will have a higher lens strength and will enlarge the image more. Microscope objectives have short focal lengths to greatly enlarge the images.

Why the objective has a larger focal length and a larger aperture than the eyepiece?

The objective of a telescope have large focal length and large aperture because large focal length enhances the magnifying power of the telescope and large aperture help in collecting large amount of light coming from the object so that a bright image is obtained.

Which lens the objective or the eyepiece should have the longer focal length?

The distance between the objective lens and the eye-piece is the sum of their focal lengths, and since the eye-piece is of small focal length, the objective lens should be of greater focal length.

Why the focal lengths of objective and eye piece lenses are kept of smaller values?

Why is eyepiece of a telescope of short focal length while objective is of large focal length explain?

What is the function of the eyepiece?

The eyepiece, or ocular, magnifies the primary image produced by the objective; the eye can then use the full resolution capability of the objective. The microscope produces a virtual image of the specimen at the point of most distinct vision, generally 250 mm (10 in.) from the eye.

Why is the objective of short focal length?

The objective and the eyepiece of a compound microscope must have short focal length so as to have larger angular magnification and magnifying power.

Why is objective of a microscope of short aperture and short focal length give reason?

The convex lens that is close to the object is known as objective lens and the lens placed near to the eye is known as eye piece. Objective lens has small focal length and small aperture because for small focal length it is necessary to have small aperture.

Why does an eyepiece have a shorter focal length?

In the second phase of magnification, an eyepiece magnifies the first image and the amount of magnification is greater with a shorter focal length. In general the eyepiece focal length will be close to the low magnification objective focal length, but much bigger than the med or high magnification objectives.

Why are both the objective and eye piece of a compound microscope have short focal length?

Why must both the objective and the eye piece of a compound microscope have short focal length? Hence, to increase magnifying power. both foand fe must be small.

How big is the eyepiece of a microscope?

The eyepiece fits inside that, and so the maximum clear aperture available for the real image from the objective is about 20 mm. The most common eyepiece magnification seems to be 10 X, which has a focal length of 25 mm.

What happens if the focus of the eye is decreased?

If it is decreased after a certain limit, the focus of eye piece would be very close to the optical centre of the eye piece and therefore the eye piece would suffer spherical aberration. The image formed by the eye piece would no longer be clear. Share Cite Improve this answer