Here is a worksheet on the Greek root phot-o. It means, simply, light, and as you will perceive, this is a very productive root at the base of many English words. It’s very productive in the life and physical sciences, giving us words like photosynthesis and photon.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.