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An angular magnification of 30 X is desired using anobject lens of focal length 1.25 cm and an eyepiece of focal length 5 cm. How will you set up the compound microscope? |
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Answer» SOLUTION :Angular magnification of the EYE piece `=1+(D)/(f_(e))` i.e.,`m_(e)=1+(25)/(5)=6` where D = 25 cm (least distance of vision) We know that`m=m_(0)m_(e)` i.e., `m_(0)=(m)/(m_(e))=(30)/(6)=5` HENCE, `because (V)/(u)=m, v=5u` using`(1)/(v)+(1)/(u)=(1)/(f_(0))` we GET `(1)/(5u)+(1)/(u)=(1)/(1.25)` `(+6)/(5u)=(4)/(5)` `because u=1.5cm`. For a real object at u = -1.5 m v = |5u| = 7.5 cm The object should be placed 1.5 cm from the object lens. |
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