6B10.25 - Wein's Law - Planetary Sunlight Intensity

Code Number:
Demo Title:
Wein's Law - Planetary Sunlight Intensity
Intensity vs. Distance
Area of Study:
Light bulbs (0.25 W, 100 W, 1000 W), Socket, Variac.

See also 6B10.25 in Optics.

Put the 1000 watt bulb on one Variac, the 100 watt bulb on another Variac and the 1/4th watt bulb on a 'D' cell battery.  Turn them all on and observe the relative intensities.  The scale of these intensities:

Intensity of sunlight as seen from Mercury = 1000 watts.

Intensity of sunlight as seen from Earth = 100 watts.

Intensity of sunlight as seen from Pluto = 1/4th watt.

  • Prof. Thomas Hocket, "Luminosity, Brightness, and Distance", TPT, Vol. 52, # 1, Jan 2014, p. 6.

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