Infinity Mirror
Big Picture
Circuits
Reflection
Light (LED)
Waves
Curved mirrors (concave and convex)
Focal point
Focal length
Principle and Concepts
Focal length- an optical system is a measure of how strongly the system converges or diverges light. (The focal length in a concave mirror is always positive while that of the convex mirror is always negative.)
Focal point- point at which initially collimated rays of light meet after passing through a convex lens, or reflecting from a concave mirror
Law of reflection- the angle of incidence is equal to the angle of reflection
Gaussian Mirror equation-known as the mirror and lens equation, relates the object distance do and image distance di to the focal length ‘f’.
Quantities and Units
1/2 * R for concave (point on the principal axis) and convex (point on the optic axis) mirror.
Formulas and Graphs
The equation is given by, where, do is the distance of the object from the mirror, di is the distance of the image formed by the mirror and ‘ f ’ is the focal length of the mirror.
1do+1di = 1f,
The object distance, and image distance equal to the focal length. Equation: 1/do + 1/di = 1/f
When the two mirrors are aligned at a 0-degree angle with each other, there are an infinite number of images. Each image is the result of an image of an image and so on. The diagram below shows the multiple images for a parallel mirror system. Images I1 and I2 are primary images. Image I1 is the image resulting from the reflection of the object O across mirror M1 and image I2 is the image resulting from the reflection of the object O across mirror M2. Image I3 is an image of image I1, found by reflecting the image I1 across mirror M2. Image I4 is an image of image I2; found by reflecting image I2 across mirror M1. This process could continue indefinitely, producing images of images for an infinite number of images.
Materials
1 - 7" Cardboard lid 1 1/2" height
1 - 9" Cardboard lid 1 1/2" height
1 - 15 bulb LED light strand- 5mm 6000mcd
1 - 7" diameter mirror
1 - 1' X 1' 1/10" thick plexiglass or real glass (whichever you prefer -- real glass will give a cleaner result)
Resistors: 510 ohms is just the right resistance if you're using a 12V power source and resistors rated for a max forward current of 30mA, and so 12V / 510 = 0.023 or 23mA. Remember V=IR.
A wooden box
3" square one-way mirrors:
3" standard mirrors:
A 12V power adaptor
Spray paint or stain: since the LEDs emit a lot of light, having a black finish works well particularly inside the box.
A dremel tool or something to drill holes into wood with
Soldering iron and solder
Glue gun
Sandpaper