
#1
Feb1113, 09:15 AM

P: 15

I googled for lens formula's proof on the internet and found one here
http://www.tutorvista.com/content/ph...nsformula.php The problem is that during the course of derivation, it is assumed that image distance is u following the sign convention. But I don't see why we have to use to sign convention once again while solving problems in ray optics... 



#2
Feb1213, 04:02 AM

P: 700

Direction has been considered.... 



#3
Feb1313, 11:49 AM

P: 15

I understand why we use sign convention ... but what's the need of using the sign convention once again ? We have already used the sign convention while deriving the formula for a lens.




#4
Feb1413, 04:15 AM

P: 700

Lens equationhttp://www.tutorvista.com/content/ph...nsformula.php 



#5
Feb1413, 06:43 AM

Sci Advisor
PF Gold
P: 11,388




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