For the first converging lens
(1/f1) = (1/u) + (1/v) ------(1)
Here,f1 = 2cm and u = 3cm
Substituting the above values in equation (1),we get
(1/v) = (1/3) - (1/2) = -(1/6)
or v = -6cm
For the second converging lens,we get
(1/5) = -(1/6) + (1/v')
or (1/v') = (1/5) + (1/6) = (11/30)
or v' = 2.73cm
The magnification of the final image produced by the lens pair is
m = (v'/u') = (2.73/6) = 0.45
A)The measurement of the final position by graphical methods is shown as below :
B)By use of the lens equation,we get
(1/5) = -(1/6) + (1/v')
or (1/v') = (1/5) + (1/6)
or v' = (30/11) = 2.73cm
The position of the final image produced by the lens pair is 2.73cm.