If F is the focal length of a convex lens and an object is placed at a distance x from the lens, then its image will be at a distance y from the lens, where F, x, and y are related by the lens equation

1
F
=
1
x
+
1
y
.
Suppose that a lens has a focal length of 4.2 cm, and that the image of an object is 8 cm closer to the lens than the object itself. How far from the lens is the object?

Question

If F is the focal length of a convex lens and an object is placed at a distance x from the lens, then its image will be at a distance y from the lens, where F, x, and y are related by the lens equation

1
F
 = 
1
x
 + 
1
y
.
Suppose that a lens has a focal length of 4.2 cm, and that the image of an object is 8 cm closer to the lens than the object itself. How far from the lens is the object?

anonymous · Answer

$$\frac{ 1 }{ F }=\frac{ 1 }{ X }+\frac{ 1 }{ Y }$$