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![[Post New]](/templates/default/images/icon_minipost_new.gif) 13 Apr 2008 07:57:03 IST
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Que. - When a object is placed at a distance of 60 cm. from a convex mirror, the magnification produced is 0.5. Where should the object be placed to get a magnification of 1/3?
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Ankur
http://www.krazzyankuriit.co.cc/ |
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![[Post New]](/templates/default/images/icon_minipost_new.gif) 13 Apr 2008 09:50:16 IST
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from first condition ..ques. tells u abt v..& hence f..
now u have f &v...calculate for u from magnification formula and mirror formula..
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Don't Dream ..Do the dream...
Rock On ....
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from the first case, applying magnification and mirror formula, we get f = +60cm.
the we use again magnification and mirror formula taking u = -3v, we get u = -120 cm which is req answer.
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![[Post New]](/templates/default/images/icon_minipost_new.gif) 14 Apr 2008 00:52:28 IST
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u= -60 cm m= 0.5 m= -v/u v= -mu = -0.5*(-60) = 30 cm According to mirror formula, 1/f=1/v+1/u =1/30+(-1/60) = 60 cm New m=1/3 m= -v/u 1/3= -v/u u=-3v Again, 1/f=1/v+1/u 1/60= 1/v+(-1/3v) v= 40 cm Thus u= - (3*40) = -120 cm
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