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What is focal length of a door peephole's lens and is it concave or convex?
Wiki User
∙ 10y ago
The lens in a door peephole is a convex lens with a very short
focal length, giving it a wide field of view. If it were on a camera,
it would be called a "Fisheye lens".
Wiki User
∙ 10y ago
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If Jane is myopic. Will she need concave or convex lenses explain?
Concave. With myopia, the focal point of the eye is in front of the retina. Concave lenses increase the distance of the focal point so that it lies on the surface of the retina.
What is a positive lens the same as?
A positive lens is also called a magnifying lens. It has convex surfaces and it has a measureable focal length where it produces an inverted image of a distant object. The power in dioptres is the reciprocal of the focal length in metres.
How does glass help you see things from a distance?
'Seeing things' depends on light rays from an object falling on one focal point a certain distance behind your corneas, the focal length. The inability for the naked eye to see things from a distance is due to the corneas' inability to converge all the light rays at the focal point, hence the fuzzy image. Glass from being able to form a convex or concave shape, can easily focus an image to your focal point
Why concave mirror is used for shaving?
Some people use concave mirror because when a man stands between the principal focus and pole of a concave mirror,he sees an enlarged,erect and virtual image of his face.this is the reason why a concave mirror of large focal length is used for shaving. concave mirrors concentrate on one focus and while shaving it concentrate on a point and the image is enlarge which prevents the face from cutting. because when a man stands between the pricipal focus and pole of a concave mirror , he sees enlarged ,erect and virtual image of his face .that is why concave mirror of large focal length is used for shaving
What would be the effect on magnification to increase the focal length of microscope and telescope?
The focal length of a telescope is directly related to the magnification in that the longer the focal length, the more magnification you get from the telsceope. How the focal length of a telescope relates to the length of the telescope itself depends on the design of the telescope. In a refracting telescope, the focal length is approximately the length of the telescope. In a reflecting telescope, the focal length is roughly two time the length of the telescope.
What is the positive lens is the same as?
The focal point F and focal length f of a positive (convex) lens, a negative (concave) lens, a concave mirror, and a convex mirror. The focal length of an optical system is a measure of how strongly the system converges or diverges light.
A concave lens is kept in contact with convex lens of focal length 20cm the combination works as a converging lens of focal length 100cmcalculate the power of concave lens?
i think it is -0.06m i.e. 6cm
The distance between a mirror and its focal point is called the?
Focal length, positive number with a concave mirror, negative for a convex mirror.
Length of a lens is the distance from the center of the lens to its principal focus?
It is called the focal length. It is equal to 1/2 times r, and is positive on concave mirrors and negative on convex mirrors.
What is the difference between the focus of concave and convex mirror?
the focal point of a concave mirror is positive while a convex is negative
How can a rough value of the focal length of a concave mirror be obtained?
rough focal length of concave mirror
Difference between focal point and focal length?
The focal point is the point where light converges after it passes through a concave lens. The focal length is the distance of the focal point to the lens. Same for a convex lens, except that the focal point is the imaginary point from where light deflected from lens seems to have emerged.
What creates an image that is reflected through a focal point?
a convex lens
Why the study was under taken of focal length of a convex lens by graphical method?
to determine the focal length of a convex mirror.
What will happen to the focal length of a concave mirror or a convex mirror when the incident violet light on them is replaced by red light?
Nothing. The focal length is defined as point where all of the light converges after passing through the lens ( for a convex mirror)and only depends on the mirror's curvature. So changing the incident light ray will cause no change in the focal length of the mirror.
Where would you stand if you wanted to see an upside down reflection of yourself in a convex mirror?
It is not possible to do this with a convex mirror. If the mirror is concave you just have be twice the focal length away from the surface of the mirror or more.
How do you find the power of lenses using focal lengths?
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 :)
