6B10.20 - Inverse Square Law - Diffuse Light Source

Code Number:
Demo Title:
Inverse Square Law - Diffuse Light Source
Inverse Square Law
Area of Study:
Overhead Mask with 4" Hole, Tracing Paper Screen, and Light Meter.

Put the mask with the 4" hole on the overhead projector and cover the hole with the tracing paper screen.  Measure the diffuse light coming from the screen with the light meter at measured distances.

  • Isabel Salinas, Marcos H. Giménez, Juan A. Monsoriu, and Juan C. Castro-Palacio, "Characterization of Linear Light Sources with the Smartphone’s Ambient Light Sensor", TPT, Vol. 56, #8, Nov. 2018, p. 562.
  • John Roeder and Art Fovargue, "Vernier Versus TI Sensors", TPT, Vol. 50, #7, Oct. 2012, p. 389.
  • John Roeder, "The Effect of Reflectors on Light Intensity", TPT, Vol. 50, #4, Apr. 2012, p. 246.
  • Haym Kruglak, "Laboratory exercise on the inverse square law*", AJP, Vol. 43, #5, May 1975, p. 449.
  • Robert Ehrlich, "L.13. Departures from the Inverse-Square Law", Turning the World Inside Out and 174 Other Simple Physics Demonstrations, p. 154 - 155.

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