Question

1. Consider a photomultiplier composed of a photocathode, nine dynodes and an anode. If each dynode ejects five electrons for each electron striking it, what is the approximate gain of the tube? A) 45 B) 1 x 105 C) 2 x 106 D) 1 x 107 E) 1 x 109 2. 2. For a scanning optical spectrometer, selection of a narrower slit width for the monochromator A) will improve the resolution of the spectrometer. B) will decrease the signal to noise ratio. C) will illustrate that resolution and signal-to-noise ratio cannot be optimized at the same time. D) may require a decrease in the scan rate to achieve the desired performance. E) All of the statements above are true. 3. If a spectrophotometer reads 85% T with the blank in place and 45% T with the sample in place, what is the absorbance? A) 0.276 B) 0.347 C) 1.65 D) Absorbance cannot be determined if the blank is not set to 100%T. E) None of the above are true.