Purpose:Show the change in resistance of a light bulb with temperature.
Description:A 60 watt incandescent light bulb is connected to a switch so that it can be quickly disconnected from the 110 VAC power to an ohmmeter. The resistance of the 60 watt bulb in operation at a high temperature is R = V^2/P = 110^2/60 = 200 ohms. The resistance cold is about 18 ohms. Turn the bulb on, then switch it to the ohmmeter. The resistance starts high and drops quickly as the bulb cools.
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Last modified on Wednesday, 30 November 2016 14:50