This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
CRT obrazovka. page is org php title Image ACRTobrazovka here br Original text vlastn kresba pekresleno uebnice fyziky original upload date br Original text Original uploader was Karpac at org cs Original text Karpac Released into the public domain by the author br Original text public domain diagram cs Czech Karpac original