Question

The sensor has is capable of a maximum measurement of about 600-700 lux. To be sure this doesnt introduce φ problems in the data collection you will need to find the position where the sensor reads a maximum value. To do this, place the light and the sensor on the optical bench and slide the sensor toward the light while watching the reading on the screen. Find the position where the reading no longer increases. This will be the shorter distance you make a measurement at. Record the intensity read by the computer and the distance between the light and sensor in your lab notebook in a table similar to the one shown below (Table 2). Measure the intensity at twelve or more varying distances. Choose distances such that more readings are taken at shorter distances than longer distances. Unplug the light (not the sensor!) and take a final reading. This is the ambient (background) light received by the sensor. Record this measurement (you only need to measure this once). Q10: Why is it a good idea to take more readings at shorter distances than longer distances in this particular experiment? Why shouldn't we just increase the distance by an even 10 cm each time?

Answer 1

because at longer distances, intensity of light decreases as intensity is inversely proportional to square of distance.

so readings should be taken at shorter distances where intensity of light is maximum. so it's good idea to take several readings at shorter distances than longer distances.

we can not increase distance with 10 cm increment as it will change value light's intensity.