Stainless Steel Mirror Sphere 13cm

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If \(m\) is positive, the image is upright, and if \(m\) is negative, the image is inverted. If \(|m|>1\), the image is larger than the object, and if \(|m|<1\), the image is smaller than the object. With this definition of magnification, we get the following relation between the vertical and horizontal object and image distances: Rays of light parallel to the principal axis of a concave mirror will appear to converge on a point in front of the mirror somewhere between the mirror's pole and its center of curvature. That makes this a converging mirror and the point where the rays converge is called the focal point or focus. Focus was originally a Latin word meaning hearth or fireplace — poetically, the place in a house where the people converge or, analagously, the place in an optical system where the rays converge. With a little bit of geometry (and a lot of simplification) it's possible to show that the focus lies approximately midway between the center and pole. I won't try this proof. A disco ball (also known as a mirror ball or glitter ball) is a roughly spherical object that reflects light directed at it in many directions, producing a complex display. Its surface consists of hundreds or thousands of facets, nearly all of approximately the same shape and size, and each having a mirrored surface. Usually it is mounted well above the heads of the people present, suspended from a device that causes it to rotate steadily on a vertical axis and illuminated by spotlights, so that stationary viewers experience beams of light flashing over them, and see myriad spots of light spinning around the walls of the room.

Jul 21, 2023 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo The small-angle approximation is a cornerstone of the above discussion of image formation by a spherical mirror. When this approximation is violated, then the image created by a spherical mirror becomes distorted. Such distortion is called aberration. Here we briefly discuss two specific types of aberrations: spherical aberration and coma. Spherical aberration In other words, in the small-angle approximation, the focal length \(f\) of a concave spherical mirror is half of its radius of curvature, \(R\): Step 4. Make a list of what is given or can be inferred from the problem as stated (identify the knowns).left. \begin{array}{rcl} \tanϕ=\dfrac{h_o}{d_o-R} \\ \tanϕ′=−\tanϕ=\dfrac{h_i}{R-d_i} \end{array}\right\} =\dfrac{h_o}{d_o-R}=−\dfrac{h_i}{R-d_i} \nonumber \] Curved mirrors come in two basic types: those that converge parallel incident rays of light and those that diverge parallel incident rays of light.

It is important to note up front that this is an approximately true relationship. We will assume it to be exactly true until becomes a problem. For many mundane applications, it's close enough to the truth that we won't care. It's not until we encounter situations requiring extreme precision that we'll deal with this aberration (as it is literally called). Astronomical telescopes should not be built with spherical mirrors. Real telescopes are made with parabolic or hyperbolic mirrors, but as I said earlier, we'll deal with this later. Figure 2.12 (a) With spherical aberration, the rays that are farther from the optical axis and the rays that are closer to the optical axis are focused at different points. Notice that the aberration gets worse for rays farther from the optical axis. (b) For comatic aberration, parallel rays that are not parallel to the optical axis are focused at different heights and at different focal lengths, so the image contains a “tail” like a comet (which is “coma” in Latin). Note that the colored rays are only to facilitate viewing; the colors do not indicate the color of the light. Using a consistent sign convention is very important in geometric optics. It assigns positive or negative values for the quantities that characterize an optical system. Understanding the sign convention allows you to describe an image without constructing a ray diagram. This text uses the following sign convention:

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A ray travelling parallel to the optical axis of a spherical mirror is reflected along a line that goes through the focal point of the mirror (ray 1 in Figure 2.9). Megaflatables inflatable mirror balls range from 1metre, right through to giant inflatablesthat are 5 metres in size – for some serious advertising appeal. We can also create a range of inflatable helium spheres sure to catch the eye of your surrounding audience. If an inflatable mirror ball isn’t quite big enough, our inflatable blimpsrange from 6metres to 8metres although we do offer giant inflatable mirror balls to suit your needs.