34. (a) Without the magnifier, ¸ = h/Pn (see Fig. 35-16). With the magnifier, letting p = Pn and i =
-|i| = -Pn, we obtain
1 1 1 1 1 1 1
= - = + = + .
p f i f |i| f Pn
Consequently,
¸ h/p 1/f +1/Pn Pn 25 cm
m¸ = = = =1 + =1 + .
¸ h/Pn 1/Pn f f
(b) Now i = -|i| -", so 1/p +1/i =1/p =1/f and
¸ h/p 1/f Pn 25 cm
m¸ = = = = = .
¸ h/Pn 1/Pn f f
(c) For f =10 cm,
25 cm 25 cm
m¸ =1 + =3.5 (case (a)) and =2.5 (case (b)) .
10 cm 10 cm