document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1120409>Question 1120409</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the intensity I of light varies inversely as the square of the distance D from the source if the intensity of Illumination on a screen 5 ft from a light is 3 foot_candles find the intensity on a screen 15 ft from the light. \r<BR>\n" );
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document.write( "A. 1(1/3) Foot-candles \r<BR>\n" );
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document.write( "B.1/3 Foot-Candles \r<BR>\n" );
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document.write( "c.1/4 Foot- Candles \r<BR>\n" );
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document.write( "D. 2 Foot - Candles  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #736079 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=736079\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Solving the problem as the other tutor did, using the formal definition of inverse proportion to find the constant of proportionality, is of course a valid method.<br><BR>\n" );
document.write( "And you should be able to use that method, as it may be required in a more complicated problem.<br><BR>\n" );
document.write( "But for a simple problem like this, I personally find it far easier simply to say that since the distance is multiplied by 3, the intensity is multiplied by 1/(3^2) = 1/9.<br><BR>\n" );
document.write( "Then 1/9 of 3 foot-candles is 1/3 foot-candle, answer B. </SPAN>\n" );
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