Light intensity and Distance from Source - Analysis of the Experiment

Analysis of the experiment to investigate the relationship between light intensity and distance.
This video shows the analysis of the experiment (including the geometry of the set up and data analysis) to determine the power of a torch via intensity measurements at measured distances and to investigate the relationship between the beam intensity and distance. The measurements were collected in the previous video ( • Light intensity and di... ).
There is a worksheet to go with this experiment so you can try the analysis yourself: www.tes.com/teaching-resource...
There is a spreadsheet available to help analysis of the data from this experiment: www.tes.com/teaching-resource...
Relevant concepts: waves, light, intensity, distance, proportionality, inverse square law, torch light.
Experiments with waves, like this one, are mandatory practicals for many physics specifications. So this is good practice for OCR physics A, AQA A-Level physics, Edexcel A-Level physics, CPAC, PAG, practical endorsement.

[@user-xz4tn9nw5h]

🙏👏👏👏👏 Ugh lovely. Thank you

[@abhinnkaushik6534]

Hi! Can you elaborate more on how to calculate the angle theta? I have a data logger but I do not know how to use it to determine the angle.

[@hapablap2088]

ok so what about the photons that are traveling in a laminar path from the source? would they not have a constant effect regardless of distance? say if we had a light source that somehow only emitted photons in a perfectly straight line, (or just a single photon) would it have any drop off in intensity with distance?

[@omnium_gatherum14]

How are you equating the units on both sides of the eqaution? On the left hand side you have intensity measured in terms of lux. On the right hand side you have the units W/m2.