Code Number: 6B10.25

Demo Title: Wein's Law - Planetary Sunlight Intensity

Condition: Good

Principle: Intensity vs. Distance

Area of Study: Astronomy

Equipment:

Light bulbs (0.25 W, 100 W, 1000 W), Socket, Variac.

Procedure:

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.

References:

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

Disclaimer

These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist. The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose. The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources. Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks. These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage. Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.

Instructional Resources and Lecture Demonstrations

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

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