Mirror Magnification
by admin on November 6th, 2007
filed under Mirrors
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US $29.93
convex mirror with image half size of object?
initially, a convex mirror with f = 30cm and magnification of 0.5 produces an image half the size of the object.
which way and by how far (from its original position) should the object move to shrink the size of the image to one quarter the size of the object?
focal length, f = 0.30 m
magnification,M = 0.5
First, we find the object distance when the magnification is 0.5.
M = - di/do , were di is the image distance, do is the object distance.
0.5 = -di/do
di = -0.5do-------------(1)
Subst (1) into the following equation.
1/f = 1/di + 1/do
-1/0.3 = -1/(0.5do) + 1/do
do = 0.30m
When magnification, m = 0.25
m = -di/do
0.25 = -di/do
di = -0.25do
1/f = 1/di + 1/do
-1/0.30 = 1/(-0.25do) + 1/do
do = 0.90m , this is the new object distance when magnification is 0.25.
The distance from original distance = 0.90 - 0.30 = 0.60m
Hope it is correct ^^
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