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L1-05. Persistence of A Filament
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L1-05. Persistence of A Filament
Purpose
To demonstrate that high-frequency AC looks like DC.
Equipment
Audio oscillator, 100 watt amplifer, and sealed beam auto headlamp.
Setup Time
5 minutes.
Images
Description
A sealed beam car headlamp is run by an oscillator and audio amplifier. Below about 20 Hz the light flickers, but above 20 Hz it appears continuous. This persistence is caused partly by your eye and partly by the heating of the filament remaining relatively constant over the period of the applied AC voltage.
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See pagesl1. light sources & light rays
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See pagesl2. plane mirrors
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See pagesl3. curved mirrors
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See pagesl4. refraction
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See pagesl5. total internal reflection
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See pagesl6. lenses
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See pagesl7. optical instruments
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See pagesl1. light sources & light rays
-
See pagesl2. plane mirrors
-
See pagesl3. curved mirrors
-
See pagesl4. refraction
-
See pagesl5. total internal reflection
-
See pagesl6. lenses
-
See pagesl7. optical instruments
Physics Lab Demos