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CHAPTER 7 QUANTUM THEORY AND ATOMIC STRUCTURE The value for the speed of light will be 3.00 x 10 8 m/s except when more significant figures are necessary, in which cases, 2.9979 x 10 8 m/s will be used. 7.1 All types of electromagnetic radiation travel as waves at the same speed. They differ in both their frequency and wavelength. 7.2 a) Figure 7.3 describes the electromagnetic spectrum by wavelength and frequency. Wavelength increases from left (10 2 nm) to right (10 12 nm). The trend in increasing wavelength is: x-ray < ultraviolet < visible < infrared < microwave < radio waves . b) Frequency is inversely proportional to wavelength according to the equation c = , so frequency has the opposite trend: radio < microwave < infrared < visible < ultraviolet < x-ray . c) Energy is directly proportional to frequency according to the equation E = h . Therefore, the trend in increasing energy matches the trend in increasing frequency: radio < microwave < infrared < visible < ultraviolet < x-ray . High-energy electromagnetic radiation disrupts cell function. It makes sense that you want to limit exposure to ultraviolet and x-ray radiation. 7.3 a) Refraction is the bending of light waves at the boundary of two media, as when light travels from air into water. b) Diffraction is the bending of light waves around an object, as when a wave passes through a slit about as wide as its wavelength. c) Dispersion is the separation of light into its component colors (wavelengths), as when light passes through a prism. d) Interference is the bending of light through a series of parallel slits to produce a diffraction pattern of brighter and darker spots. Note: Refraction leads to a dispersion effect and diffraction leads to an interference effect. 7.4 Evidence for the wave model is seen in the phenomena of diffraction and refraction. Evidence for the particle model includes the photoelectric effect and blackbody radiation. 7.5 a) Frequency: A > B > C b) Energy: A > B > C c) Amplitude: A > C > B d) Since wave A has a higher energy and frequency than B, wave A is more likely to cause a current. e) Wave B is more likely to be infrared radiation since Wave C has a longer wavelength than B. 7.6 Radiation (light energy) occurs as quanta of electromagnetic radiation, where each packet of energy is called a photon. The energy associated with this photon is fixed by its frequency, E = h . Since energy depends on frequency, a threshold (minimum) frequency is to be expected. A current will flow as soon as a photon of sufficient energy reaches the metal plate, so there is no time lag. 7.7 Plan: Wavelength is related to frequency through the equation c = . Recall that a Hz is a reciprocal second, or 1/s = s 1 . Assume that the number 950 has three significant figures. ... View Full Document

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