🌐EnglishEnglishDeutschEspañolPortuguêsفارسیEntityQ2068617· pop 5· linked from 80 articlespencilAlso known as pencil of raysbeam of electromagnetic radiation or charged particlesAvailable in 5 languagesEspañolDeutschPortuguêsفارسیvia Wikidata sitelinks · CC0ConnectionsInternational Standard Book NumberEntityopticsEntityCategoriesAntennas (radio)Geometrical opticsRadiation therapy