A convex  lens has focal length of  30 cm. at what distance should object be placed  from the lens so  that it  forms an image  at 60 cm on  other  side of  the lens?  Find the  magnification produced by  the  lens

Asked by sisugsgsgsysyhshz | 9th Jun, 2017, 05:52: PM

Expert Answer:

begin mathsize 12px style For space convex space lens colon
straight f equals 30 space cm semicolon space straight v equals plus 60 space cm
From space lens space formula comma
1 over straight f equals 1 over straight v minus 1 over straight u
1 over straight u equals 1 over straight v minus 1 over straight f equals 1 over 60 minus 1 over 30
1 over straight u equals fraction numerator negative 1 over denominator 60 end fraction
straight u equals negative 60 space cm
Therefore comma space the space object space should space be space placed space at space straight a space distance space of space 60 space cm space
from space the space lens space on space the space left space hand space side.
From space magnification space formula comma
straight m equals straight v over straight u equals fraction numerator 60 over denominator negative 60 end fraction equals negative 1
Hence comma space the space image space is space of space the space same space size space of space the space object space but space is space inverted. end style

Answered by Romal Bhansali | 11th Jun, 2017, 01:08: PM

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