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LAMP ANALYSIS

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  P447-448

2026-08-19

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LAMP ANALYSIS

Once again, consider the hit-and-run case described earlier in this chapter. Suppose the facts of the case are altered so that the incident took place at dusk and a question arose as to whether the headlights were on at the time. If a headlight breaks during the impact, it is usually possible to determine its status at the time of impact.

As shown in Figure 1, if a light filament is hot and then the vacuum in the light is broken, then oxygen in the air will react with the tungsten in the filament resulting in the formation of oxides on the surface of the filament. If the filament is not on at the time the lamp is breached, then no reaction will take place and no tungsten oxides will be seen. The filament in Figure 1 was photographed with an SEM.

FIGURE 1 A headlight filament that was on when the lamp was broken.