6B40.10 - Variac and Light Bulb
See also 6B40.10 in Optics.
Video Credit: Jonathan M. Sullivan-Wood.
Put the 1 KW light bulb onto the variac and turn up slowly. At low voltages the large filament area should look red to a dull orange. As you now slowly turn up the voltage the filament will get hotter and the corresponding color will be more and more towards white.
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