In the figure below, the converging lens\' focal length is 15 cm, d = 17.8 cm, a
ID: 1277366 • Letter: I
Question
In the figure below, the converging lens' focal length is 15 cm, d = 17.8 cm, and the diverging lens' focal length is -14.8 cm. A 1.4 cm tall object is 9.1 cm to the left of the converging lens.
a) Where is the image formed by the converging lens, measured from that lens (using negative for a virtual image)?
________cm
(b) How tall is the image formed by the converging lens (using negative for an inverted image)?
________ cm
(c) Where is the image formed by the diverging lens, measured from that lens (using negative for a virtual image)?
________ cm
(d) How tall is the image formed by the diverging lens (using negative for an inverted image)?
_______ cm
Explanation / Answer
1/f1 = 1/v1 - 1/u1
1/15 = 1/v1 + 1/9.1
1/v1 = 1/15 - 1/9.1
v1 = - 23.14 cm ( answer a )
the image is formed by the converging lens is to the left of the lens at 23.14 cm
hi1/ho1 = v1/u1
hi1/1.4 = -23.14/-9.1
hi1 = 3.56 cm (answer b)
now
1/f2 = 1/v2 - 1/u2
-1/14.8 = 1/v2 + 1/40.94
1/v2 = -1/14.8 - 1/40.94
v2 = - 10.87 cm ( answer c to the left of the diverging lens)
hi2/ho2 = v2/u2
hi2/3.56 = -10.87/-40.94
hi2 = 0.95 cm (answer d)