![]() ![]() The orbiting electron in Bohr’s model is assumed not to emit any electromagnetic radiation while moving about the nucleus in its stationary orbits, but the atom can emit or absorb electromagnetic radiation when the electron changes from one orbit to another. The Bohr model retains the classical mechanics view of circular orbits confined to planes having constant energy and angular momentum, but restricts these to quantized values dependent on a single quantum number, n. If classical electromagnetic theory is applied, then the Rutherford atom would emit electromagnetic radiation of continually increasing frequency (contrary to the observed discrete spectra), thereby losing energy until the atom collapsed in an absurdly short time (contrary to the observed long-term stability of atoms). If the requirements of classical electromagnetic theory that electrons in such orbits would emit electromagnetic radiation are ignored, such atoms would be stable, having constant energy and angular momentum, but would not emit any visible light (contrary to observation). According to classical mechanics, the Rutherford model predicts a miniature “solar system” with electrons moving about the nucleus in circular or elliptical orbits that are confined to planes. The area inside a circle is given by A = πr 2, where the radius r is one-half of the diameter.)īoth involve a relatively heavy nucleus with electrons moving around it, although strictly speaking, the Bohr model works only for one-electron atoms or ions. How many data bits can be contained on the disk? If a Blu-ray disk can hold 9,400,000 pages of text, how many data bits are needed for a typed page? (Hint: Determine the area of the disk that is available to hold data. Disks have an outside diameter of 120 mm and a hole of 15-mm diameter. The data density of a Blu-ray disk using a 405-nm laser is 1.5 × 10 7 bits mm −2.If the 405-nm laser is used in a Blu-ray player, what is the closest that information can be stored on a Blu-ray disk? Numerical aperture is a measure of the size of the spot of light on the disk the larger the NA, the smaller the spot. The ideal resolution of a player using a laser (such as a Blu-ray player), which determines how close together data can be stored on a compact disk, is determined using the following formula: Resolution = 0.60( λ/NA), where λ is the wavelength of the laser and NA is the numerical aperture.How many photons of light are produced by the laser in 1 hour? A Blu-ray laser has a power of 5 milliwatts (1 watt = 1 J s −1). ![]() ![]() In what region of the electromagnetic spectrum is this radiation? What is its frequency?
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