In the figure below, a pinecone is at distance p_1 = 1.8 m in front of a lens of
ID: 1605324 • Letter: I
Question
In the figure below, a pinecone is at distance p_1 = 1.8 m in front of a lens of focal length f = 0.47 m. A flat mirror is at distance d = 1.8 m behind the lens. Light from the pinecone passes rightward through the lens, reflects from the mirror, passes leftward through the lens, and forms a final image of the pinecone. What is the distance between the lens and the final image? _______ m What is the overall lateral magnification of the pinecone? _______ Describe the final image. (Select all that apply.) real virtual upright inverted to the left of the lens to the right of the lensExplanation / Answer
a)
for the lens :
do = object distance = 1.8 m
f = focal length = 0.47 m
di = image distance
using the lens equation
1/do + 1/di = 1/f
1/1.8 + 1/di = 1/0.47
di = 0.64 m
for the mirror :
do = object distance = 1.8 - 0.64 = 1.152
di = image distance from the mirror = 1.152
for lens again
do = object distance = 1.8 + 1.152 = 2.952 m
using the lens equation
1/do + 1/di = 1/f
1/2.952 + 1/di = 1/0.47
di = 0.56 m
b)
m1 = - 0.64 /1.8 = - 0.36
m2 = - 0.56 /2.952 = - 0.19
m = m1 m2 = (-0.36) (-0.19) = 0.0684
c)
real
upright
to the left of lens