given  Â
image distance   di   =
7.00Â Â Â m
= 700.0Â Â Â cm
magnification   m   =   Â
- 73.5 ( as image is real)
object distance   =   do
focal length   =   f
a.  Â
magnification   m   =   -
di/do
- 73.0Â Â Â =Â Â Â - 700.0 / do
slide distance   do   = 700.0 /
73.5
= 9.52 cm =Â Â Â 0.0952
b.  Â
Image is inverted as magnification is negative.
c.  Â
1/f   =   1/di   -   1/do
=Â Â Â 1/700.0Â Â Â -Â Â Â 1/(
- 9.52)
( do is taken as - ve as the object lies to the left of
lens)
focal length   f   = 700.0 * 9.52
/ (700 + 9.52)
= 9.39 cm
=Â Â Â 0.0939 m
d.  Â
Since focal length is + ve, lens is converging.
