General Equipment

Here is the set of equipment we need for this lab :

• Pasco Optics bench
• Laser Diode
• Multiple Slit Disk
• Screen
• paper and tape
• small ruler

Multiple slit "mosaic"

There are several parts of the disk we will use: double slits, variable double slit, multiple slits. The values for the slit separations (d) and slit widths (a) are given on the dial ... and a measured in MM (millimeters)!

It is recommended that you make all your measurements in mm (and the laser wavelength is given in mm in the lab manual).

Alignment of the laser and screen

The optics bench makes it very easy to align everything (and measure some of the distances). We don't care how far away the laser is from the screen, but we do need to know the distance between the slits and the screen.

It appears that the slits are 2.5 cm in front of the little "tab" on the side of the slit holder. So, if you set the slit holder tab at 7.5 cm (as shown above on the right), that should place the slits at 10 cm.

Then, on the other end, place the screen at 110 cm. This gives 100 cm between the slits and the screen ... or 1000 mm.

(There is a place on the data/question sheets for the distance L - from the slits to the screen.)

Paper on Screen

Once you find a pattern on the screen - tape a piece of paper to the screen. You can write on this paper to mark the dots, and then take it off to do the measurements (you could even write some notes on the paper as you go along).

Do NOT write directly on the white screens! That is what the paper is for!!!