What is the eyepiece?
2 answers:
Answer: SOURCE-WIKIPEDIA
An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is so named because it is usually the lens that is closest to the eye when someone looks through the device. The objective lens or mirror collects light and brings it to focus creating an image. The eyepiece is placed near the focal point of the objective to magnify this image. The amount of magnification depends on the focal length of the eyepiece. An eyepiece consists of several "lens elements" in a housing, with a "barrel" on one end. The barrel is shaped to fit in a special opening of the instrument to which it is attached. The image can be focused by moving the eyepiece nearer and further from the objective. Most instruments have a focusing mechanism to allow movement of the shaft in which the eyepiece is mounted, without needing to manipulate the eyepiece directly. The eyepieces of binoculars are usually permanently mounted in the binoculars, causing them to have a pre-determined magnification and field of view. With telescopes and microscopes, however, eyepieces are usually interchangeable. By switching the eyepiece, the user can adjust what is viewed. For instance, eyepieces will often be interchanged to increase or decrease the magnification of a telescope. Eyepieces also offer varying fields of view, and differing degrees of eye relief for the person who looks through them.
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Answer:
(a) The second wire will be stretched by 2 mm
(b) The third wire will be stretched by 0.25 mm
Explanation:
Tensile stress on every engineering material is given as the ratio of applied force to unit area of the material.
σ = F / A
Tensile strain on every engineering material is given as the ratio of extension of the material to the original length
δ = e / L
The ratio of tensile stress to tensile strain is known as Young's modulus of the material.
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<u>Part A</u>
cross sectional area and applied force are the same as the original but the length is doubled
The second wire will be stretched by 2 mm
<u>Part B</u>
a third wire with the same length but twice the diameter of the first
e₁ = ¹/₄ x 1 mm = 0.25 mm
The third wire will be stretched by 0.25 mm