A converging lens with a focal length of 11.0 cm forms a virtual image 7.80 mm tall, 16.2 cm to the right of the lens. a) Determine the position of the object. s=?cm b) Determine the size of the object. [y]= ?cm c) Is the image upright or inverted? d) Are the object and image on the same side or opposite sides of the lens? Solution Given focal length of the converging lens is f = 11 cm , forming a virtual image of height y \' = 7.80 mm = 0.780 cm and image distance s\' = 16.2 cm a) from lens equation 1/s + 1/s\' = 1/f 1/s = 1/f-1/s\' 1/s = 1/11 -1/16.2 s = 34.26 cm object distance is s = 34.26 cm b) the size of the object is y = ? from lateral magnification m = -s\'/s = y\'/y so y = -y\'*s/s\' y = 0.78*34.26/16.2 y = 1.6496 cm c) the image formed is an inverted image d) the object and image are on the opposite sides of the lens .

1. A converging lens with a focal length of 11.0 cm forms a virtual image 7.80 mm tall, 16.2 cm to
the right of the lens.
a) Determine the position of the object. s=?cm
b) Determine the size of the object. [y]= ?cm
c) Is the image upright or inverted?
d) Are the object and image on the same side or opposite sides of the lens?
Solution
Given
focal length of the converging lens is f = 11 cm , forming a virtual image of
height y ' = 7.80 mm = 0.780 cm and
image distance s' = 16.2 cm
a)
from lens equation
1/s + 1/s' = 1/f
1/s = 1/f-1/s'
1/s = 1/11 -1/16.2
s = 34.26 cm
object distance is s = 34.26 cm
b)

2. the size of the object is y = ?
from lateral magnification
m = -s'/s = y'/y
so y = -y'*s/s'
y = 0.78*34.26/16.2
y = 1.6496 cm
c) the image formed is an inverted image
d) the object and image are on the opposite sides of the lens