A 4.3 cm long insect is perpendicular to the optical axis of a thin lens; the bu
ID: 1327000 • Letter: A
Question
A 4.3 cm long insect is perpendicular to the optical axis of a thin lens; the bug is 5.8 cm away from the lens. The lens forms an inverted image of the insect which is 0.9 cm long on a screen behind the lens. (Use three significant figures.)
a. How far behind the lens is the screen?______cm
b. What is the lens' focal length (pay attention to sign)?______cm
c. If the insect were instead only 0.27 cm from the lens, what would the image distance be?(pay attention to sign)_____cm
d. Could the new image be projected on a screen?
yes no possibly
Explanation / Answer
(a)
from the given
object height = 4.3 cm
image height = 0.9 cm
magnification
m = (v / u) = (image diatsnce / object distance)
= (0.9 / 4.3)
image distance
v = 1.21cm
(b)
to get the focal length use
(1 / f) = (1 / v) - (1 / u)
(c)
u = 0.27 cm
using f solve for the image distance v
(d)
yes the new image can be caught on the screen but it becomed blurr because the object is very nearer to the lens