A diverging lens has a focal length of -14.0 cm. Locate the images for each of the following object distances. For each case, state whether the image is real or virtual and upright or inverted, and find the magnification. (a) 28.0 cm ______________ cm real, erect real, inverted virtual, erect virtual, inverted magnification ________________ X (b) 14.0 cm ______________ cm virtual, erect virtual, inverted magnification ___________________ ? (c) 7.0 cm _______________ cm real, erect real, inverted virtual, erect virtual, inverted magnification __________________ ? Solution (a) object distane s = 28 cm focal length f = -14 cm image distance s\' = ? 1/s + 1/s\' = 1/f 1/28 + 1/s\' = -1/14 s\' = -9.33 cm image distance 9.33 infront of the lens virtual erect magnification m = -s\'/s = 0.33 ============================== (b) object distane s = 14 cm focal length f = -14 cm image distance s\' = ? 1/s + 1/s\' = 1/f 1/14 + 1/s\' = -1/14 s\' = -7 cm image distance 7 cm infront of the lens virtual erect magnification m = -s\'/s = 0.5 ========================================= (c) object distane s = 7 cm focal length f = -14 cm image distance s\' = ? 1/s + 1/s\' = 1/f 1/7 + 1/s\' = -1/14 s\' = -4.67 cm image distance 4.67 infront of the lens virtual erect magnification m = -s\'/s = 0.67 .

1. A diverging lens has a focal length of -14.0 cm. Locate the images for each of the following
object distances. For each case, state whether the image is real or virtual and upright or inverted,
and find the magnification.
(a) 28.0 cm
______________ cm
real, erect
real, inverted
virtual, erect
virtual, inverted
magnification ________________ X
(b) 14.0 cm
______________ cm
virtual, erect
virtual, inverted
magnification ___________________ ?
(c) 7.0 cm
_______________ cm
real, erect
real, inverted
virtual, erect
virtual, inverted
magnification __________________ ?

2. Solution
(a)
object distane s = 28 cm
focal length f = -14 cm
image distance s' = ?
1/s + 1/s' = 1/f
1/28 + 1/s' = -1/14
s' = -9.33 cm
image distance 9.33 infront of the lens
virtual
erect
magnification m = -s'/s = 0.33
==============================
(b)
object distane s = 14 cm
focal length f = -14 cm
image distance s' = ?

3. 1/s + 1/s' = 1/f
1/14 + 1/s' = -1/14
s' = -7 cm
image distance 7 cm infront of the lens
virtual
erect
magnification m = -s'/s = 0.5
=========================================
(c)
object distane s = 7 cm
focal length f = -14 cm
image distance s' = ?
1/s + 1/s' = 1/f
1/7 + 1/s' = -1/14
s' = -4.67 cm
image distance 4.67 infront of the lens
virtual
erect
magnification m = -s'/s = 0.67