The Lens Equation

The Lens Equation

1. The following is the lens equation that relates the object distance (u), image distance (v) and the focal length. $$\frac{1}{u}+\frac{1}{v}=\frac{1}{f}$$
2. When using the lens equation to solve problem, it's important to note the positive negative sign of u, v and f.
3. Table below give the conventional symbol and sign for u, v and f.

	Positif	Negatif
u	Real object	Virtual object
v	Real image	Virtual image
f	Convex lens	Concave lens

Linear Magnification

The linear magnification is a quantity that indicates the ratio of the height of the image to the height of the object.

$$m=\frac{v}{u}=\frac{h_i}{h_o}$$
m = linear magnification
u = distance of object
v = distance of image
h_i = heigth of image
h_o = heigth of object