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प्रश्न
A convex lens of a focal length 5 cm is used as a simple microscope. Where should an object be placed so that the image formed by it lies at the least distance of distinct vision (D = 25 cm)?
उत्तर
f = 5 cm
v = - 25 cm
We know that, `1/"v" - 1/"u" = 1/"f"`
`=> -1/25 - 1/"u" = 1/5`
`=> -1/"u" = 1/25 + 1/5`
`=> 1/"u" = -((1+5)/25) = - 6/25`
`therefore "u" = - 25/6 "cm" = - 4.16` cm
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