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A compound microscope has an objective of focal length `1 cm` and an eye piece of focal length `2.5 cm` away frm the object has to be placed at a distance of `1.2 cm` away from the objective for normal adjustment. Find the angular mignification and length of the microscope tube. |
Answer» Here, `f_(0) = 1 cm, f_(e) = 2.5 cm`. `u_(0) = - 1.2 cm, m = ? L = ?` As `(1)/(v_(0)) - (1)/(u_(0)) = (1)/(f_(0))` `:. (1)/(v_(0)) = (1)/(f_(0)) + (1)/(u_(0)) = (1)/(1) - (1)/(1.2) = (0.2)/(1.2)` `v_(0) = 1.2//0.2 = 6 cm` As `m = (v_(0))/(|u_(0)|)(1 + (d)/(f_(e)))` `:. m = (6)/(1.2)(1 + (25)/(2.5)) = 55` `L = v_(0) + f_(e) = 6 + 2.5 = 8.5 cm` |
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