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Power (F)= 1/focal length (f)
focal length f, is measured in meters
the power, F, is in dioptres (D)
In converging or convex lenses the power is positive
In diverging or concave lenses, the power is negative
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Why do thick lenss show chromatic aberration but thin lenss do not?
because thick lenses have small focal length . this causes chromatic aberration. hence it can be minimised by increacing the focal length of lens or by using thin lenses which have high focal length.
Which lens of a microscope is responsible for producing a magnified image on the inside of the microscope that is not seen directly by the person using the microscope?
to produce a magnified image, a microscope uses 2 convex lenses which have relatively short focal lengths to magnify small, close objects.
Two lenses one of focal length plus 20cm and another of focal length -15cm are placed in contact What is the focal length nature and power of combination?
1) Simply, changing to diopters (inverse of focal length in meters), D1=5 and D2=-6.666... , then their difference is -1.666... which corresponds to F=-0.6m or -60cm.2) Using formula for two lenses: 1/F = 1/F1 + 1/F2 - d/(F1 * F2), where d = distance between lenses (here equal to zero), 1/F = 1/20 - 1/15 = -1/60; so F=-60 (cm).
Why does one need a telephoto lens for landscape photography?
Someone needs a telephoto lens for landscaping photography because it allows you to capture a wide range of perspectives by using different focal lenses.
Microscope Are all three colored threads in focus when using scanning power?
No they are not because of the focal plane. The focal plane is the the ability to visualize one item under the microscope over the others.
Do magnifying lenses power solar cars better?
There are some experiments using magnifying lenses to focus the sun's rays on a particularly strong solar cell (do a search for Suncube). Check the various Solar Car Trials to see if any are using magnifying lenses. They certainly could.
Can you give me a sentence using the word focal?
the focal length of most binoculars is .50
What Camera Equipment Do You Need?
The type of camera equipment you need depends on what type of pictures you will be taking. Lenses will be one the biggest investments, so you will want to research lens brands before buying. Different types of photography requires different focal lengths, so pick lenses specific to your type of photography. The on-board flash is not a powerful one, so you will need to buy an external flash if you will be taking pictures inside. A photography light is essential if you will be taking portraits inside or using a light box to close up photos.
What are the two possibilities for an image formed by a convex lens?
Convex (I prefer converging lenses) lenses are thicker in the middle than at the edges. This causes the rays to converge towards the principle axis (line running through the center of the lens perpendicular to the surface). two images will be formed. When the object you are viewing is farther from the lens than the focal length you will have an inverted real image. This image can be enlarged (when the object is between the focal length and twice the focal length), the same size (when the object is twice the focal length from the lens) or reduced (when the object is beyond twice the focal length). When the object is closer to the lens than the focal length you are using the lense as a magnifying glass and you will have an upright virtual image.
What precautions should you take when you are using high power lenses?
You must be very careful that you don't crush the cover slip and the slide.
How do you make a simple telescope?
You can assemble a simple telescope by using two lenses, one weak convex lens (this is thicker at the centre) as the objective and a stronger concave lens ( thinner at the centre) as the eyepiece. then, with simple manipulation you can determine the focal length of your lenses, double this calculation for length of tubing required to mount lenses and assemble a gallilean style telescope. ******* An online visual guide can help you understand what is involved in building a telescope.
How do you increase the magnification power of a telescope?
You need to rotate the lenses round to get the best magnification then use the wheels on the side to bring it into focus. If this does not meet your requirement's then you need a better microscope.
