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Name:  Philip R.
Status: student
Age: 17
Location: N/A
Country: N/A
Date: 2000-2001


Question:
Dear scientist, I am a student in England and need your help, I am currently running an investigation to see whether steel has comon reflective properties as a mirror has, I know that the Energy given out from a bulb is 1/r(squared) but i am not sure how to follow this equation when it is reflected off a mirror into a L.D.R. Please can you help me?


Replies:
If the mirror is planar, all you need to do is measure the distance the light travels from the source to the detector including its reflection, and that is your r. However, if the mirror is curved, the intensity of the light reaching the detector depends on how much the mirror focuses or defocuses it. For that, you need to figure out from your r^(-2) formula how much light reaches the mirror, and then you need to determine how much of that light reaches the detector.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois



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