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Why is the focal length of the objective lens in a microscope short?
Wiki User
∙ 12y ago
To improve magnification. Also so that we can get a real and inverted image
Wiki User
∙ 12y ago
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What are the optical parts of the microscope. How does it achieve magnification and Resolution?
The main parts of an optical microscope are: the eyepiece, objective lense and light source (sometimes a mirror). The objective lense has a short focal length so it produces an image a little bit up the microscope's tube which is then magnified by the eyepiece. Resolution is dependant on the numerical appeture of the lense and the wavelenght of the light source used.
How do you work a microscope?
A confocal microscope works by a laser shining on two mirrors mounted on motors which allows it to scan the sample then the emitted light is focued through the pinhole to a detector which relays an image to the lens.
Why convex lens of short focal length is preferred on magnifying glass?
The power of a lens is measured in dioptres which is the reciprocal of the focal length in metres. A 5-dioptre lens would allow you to see something at a distance of 20 cm, while a 20-dioptre lens would allow the object to be seen from 5 cm (2 inches) so it would be more effective as a magnifying glass. Your arms are short.
How does a concave lens correct nearsightedness?
The eye lens may become too thick & its focal length is reduced. the ciliary muscles are not able to relax sufficiently to make the eye lens thin when viewing distant objects. So, they are unable to increase the focal length of the lens & the image is formed before retina. Since short sightedness occurs due to excessive convergence of light rays by the eye lens, it can be corrected by using a diverging lens, i.e, a concave lens. A properly chosen focal length of a concave lens compensates the extra convergence of the eye lens thus, removing the defect. The scientific name of short sightedness is myopia.
Focal distance of a concave lens is always what?
To my understanding of psychology, the lens convexity in distant vision is increased in order to better take in the visual stimuli. To focus visual stimuli on the fovea (focus point) of the retina, the lens undergoes a process of adjusting called "accommodation," and it becomes more convex to ensure that distant objects reach the retina. A failure to properly accommodate leads to nearsightedness (faraway objects falling short of retina) or farsightedness (nearby objects falling past retina)
What is the significance of the term compound in describing a modern light microscope?
A compound microscope contains an objective lens with a very short focal length and an eyepiece with a longer focal length. Both lens are mounted in the same tube.
What is the difference of compound microscope from a simple microscope?
compound microscope consists of 2 lences of short focal length & short aurpature .
What are the optical parts of the microscope. How does it achieve magnification and Resolution?
The main parts of an optical microscope are: the eyepiece, objective lense and light source (sometimes a mirror). The objective lense has a short focal length so it produces an image a little bit up the microscope's tube which is then magnified by the eyepiece. Resolution is dependant on the numerical appeture of the lense and the wavelenght of the light source used.
The magnification of a telescope is changed by changing the?
The magnification of a telescope is the ratio of the effective focal length of the objective to the focal length of the eyepiece. For example, a small telescope's objective may have a focal length of 800mm. When an eyepiece with a focal length of 25mm is used, the magnification is 800/25 = 32. The term "effective focal length" refers to the focal length of the objective as affected by any "focal extender". Many telescopes are designed to have a short total size, but high power, by "folding" the optical path. A mirror-type objective with a focal length of perhaps 800mm is coupled with a smaller curved mirror that intercepts the last 200mm and extends it to 800mm, a 4x extension, so that the effective focal length of that objective is 3200mm. Use that with a 25mm eyepiece and the magnification is 3200/25 = 128. By the way, if a telescope is smaller than you are, it is seldom much use to view using a magnification greater than 50 to 100. Most objects are best viewed at relatively low powers such as 30 or so.
The magnification of a telescope is changed by changing the what?
The magnification of a telescope is the ratio of the effective focal length of the objective to the focal length of the eyepiece. For example, a small telescope's objective may have a focal length of 800mm. When an eyepiece with a focal length of 25mm is used, the magnification is 800/25 = 32. The term "effective focal length" refers to the focal length of the objective as affected by any "focal extender". Many telescopes are designed to have a short total size, but high power, by "folding" the optical path. A mirror-type objective with a focal length of perhaps 800mm is coupled with a smaller curved mirror that intercepts the last 200mm and extends it to 800mm, a 4x extension, so that the effective focal length of that objective is 3200mm. Use that with a 25mm eyepiece and the magnification is 3200/25 = 128. By the way, if a telescope is smaller than you are, it is seldom much use to view using a magnification greater than 50 to 100. Most objects are best viewed at relatively low powers such as 30 or so.
If a telescope has an objective lens of 3 inches what is the focal length?
The size (diameter) of a lens does not determine its focal length. The amount of curvature of the lens does. Citing a diameter for a lens doesn't help us find the focal length. Lenses are ground to specifications that allow short or long focal length. The more curved the lens, the shorter the focal length. You can see this if we specify a given curvature and then start to "flatten" the lens. The focal length will get longer and longer as the lens is flattened. When the lens is flat (has to curvature) the lense has an infinite focal length, just like a piece of flat glass.
For a research telescope (with a long focal length) would the thickness be greater or less than for a backyard telescope (with a short focal length)?
Technically the shorter the focal length, the thicker the mirror. But some short focal length telescopes have relatively thin mirrors all the same.
What uses a long focal length a short focal length lens and has an inverted image?
a camera? Or an eye? Something like that. Weird question
What is a sentence with the word focal?
Wide-angle lenses have a short focal length. The focal character of my short story is a ten-year-old boy.
Why cant opaque objects be veiwed under a compound microscope?
That is certainly not true. A "compound" microscope is one that has an objective AND an ocular. Typically the front focal distance is so short that illumination through the specimen is most common. A "simple" microscope has only one magnifying lens group, not two or more. Short front focus makes lighting from the side more difficult but not impossible or even rare.
Which lens provides more magnification-a low power or a high power?
A lens of short focal length has a greater power (than a lens of large focal length)
Construction of the simple microscope?
A simple microscope consists of a single convex lens with a short focal length. This lens is typically mounted on a frame or stand that holds it in place and allows for adjustment. The object to be viewed is placed in front of the lens and the viewer looks through the lens to see the magnified image. The magnification is determined by the focal length of the lens, which can range from 5x to 250x. The resolution of the microscope is determined by the quality of the lens. The frame or stand is typically made of metal or plastic and may include a focusing mechanism.
