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The Bunsen Photometer

المؤلف:  GEORGE A. HOADLEY

المصدر:  The Bunsen Photometer

الجزء والصفحة:  p-441

2025-12-16

506

consists of a screen of unglazed white paper having in the middle a spot of paraffin or oil. It is sometimes called the grease spot photometer. Figure 1 shows the arrangement of the spot box with two mirrors M and M' so inclined that the two images of the spot

will be seen side by side. The sources of light to be compared are placed one on each side of the screen and at such distances that the spot is invisible. This takes place when the same amount of light strikes upon each side of the screen, from the two light sources. Applying the law of light intensity we have from Fig. 1

hence