InterviewSolution
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InterviewSolution
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A cardsheet divided into squares each of size `1 mm^(2)` is being viewed at a distance of `9 cm` through a magnifying glass (a conerging lens of focal length `10 cm`) held close to the eye. (a) What is the magnification produced by the lenas ? How much is the area of each square to the virtual image ? (b) What is the angular magnification (magnifying power) of the lens ? ( c) Is the magnification in (a) equal to the magnifying power in (b) ? Explain |
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Answer» (a) Here, area of each (object) square `= 1 mm^(2), u = -9 cm, f = 10cm`. As `(1)/(v) - (1)/(u) = (1)/(f) :. (1)/(v) = (1)/(f) + (1)/(u) = (1)/(10) - (1)/(9) = (9 - 10)/(90) = -(1)/(90)` `v = -90 cm`. Magnification, `m = (v)/(|u|) = (90)/(9) = 10` `:.` Area of each square in virtual image `= (10)^(2) xx 1 = 100 sq. mm` (b) Magnifying power `= (d)/(u) = (25)/(9) = 2.8` ) c) No, magnification in (a) which is `(v//u)` cannot be equal to magnifying power in (b) which is `(d//u)` unless `v = d` i.e. image is located at the least distance of distinct vision. |
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