In a compound microscope, the focal lengths of two lenses are 1.5 ~cm and 6.25 ~cm . An object is placed at 2 ~cm from the objective and the final image is formed at 25 ~cm from the eye lens. The distance between the two lenses is .............. (in cm ).

Step-by-step solution

For, objective, u=-2 ~cm , f=1.5 ~m By 1 v - 1 u = 1 f , we have, 1 v = 1 1.5 - 1 2 v=6 ~cm For eyepiece, v=-25 ~cm , f=6.25 ~cm aligned Using 1 v - 1 u & = 1 f , we get 1 u & = 1 -25 - 1 6.25 u & =-5 ~cm aligned So, distance between two lenses = 11 cm.