A light, flashing regularly, consists of cycles, each cycle having a dark phase and a

Chapter 5, Problem 5.4.24

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A light, flashing regularly, consists of cycles, each cycle having a dark phase and a light phase. The frequency of this light is measured in cycles per second. As the frequency is increased, the eye initially perceives a series of flashes of light, then a coarse flicker, a fine flicker, and ultimately a steady light. The frequency at which the flickering disappears is called the fusion frequency.18 Table 5.21 shows the results of an experiment19 in which the fusion frequency F was measured as a function of the light intensity I. It is modeled by F = a ln I + b. (a) Find ln I for each value of I, and then use linear regression on a calculator or computer to estimate a and b in the equation F = a ln I + b. (b) Plot F against ln I, showing the data points and the line. (c) Plot F against I, showing the data points and the curve and give its equation. (d) The units of I are arbitrary, that is, not given. If the units of I were changed, which of the constants a and b would be affected, and in what way?