An angular magnification (magnifying power ) of 30x is desired using on objective of focal length 1.25 cm and an eyepiece of focal length 5cm. How will you set up the compound microscope ?

Explanation

`m_(0) = (v_(0))/(-u_(0)) , m_(e) = 1 + (D)/(f_(e)) , m = m_(o) m_(e)`
`m_(e) = 1 + (25)/(5) = 6 , m = 30 " " m_(0) = (m)/(m_(e)) = (30)/(6) = 5 `
` m_(0) = (v_(0))/(-u_(0)) " i.e," 5 = (v_(0))/(-u_(0)) , v_(0) = - 5u_(0), f_(0) = 1.25 cm " " therefore (1)/(v_(0)) - (1)/(u_(0)) = (1)/(f_(0))`
`(1)/(-5u_(0)) - (1)/(u_(0)) = (1)/(1.25)`
Sovling `rArr u_(0) = - 1.5 cm and v_(0) = + 7.5 cm`
Then `(1)/(v_(e)) - (1)/(u_(e)) = (1)/(u_(e)) = (1)/(f_(e)) , (1)/(-25) - (1)/(u_(e)) = (1)/(5) `
`- (1)/(u_(e)) = (1)/(5) + (1)/(25) = (6)/(25) " " therefore u_(e) = (-25)/(6) = - 4.2 ` cm
Distance between objective and eyepiece = `v_(0) + |u_(e) | = 7.5 + 4.2 = 11.7 ` cm
Position of the object from objective = `|u_(0)| = 1.5 ` cm