Inverse Square law: Materials

For this part of the experiment, you should have:

• A Desk Top Star
• A light detector circuit
• A small meter with alligator clips
• A ruler or meter stick

We will use a special electronic circuit to measure the brightness of the light. The curcuit consists of a "photo-diode" light detector, which generates a small electric current when a light is shining on it. A integrated chip called an "op-amp" amplifies this current so that you can easily see its effect using the meter. The size of the current is proportional to the brightness of the light.