🌐EnglishEnglishDeutschEspañolItalianoPortuguêsРусскийالعربية한국어中文日本語EntityQ903200· pop 14· linked from 10 articlesHollow-cathode lampspectral line source used in physics and chemistryConnectionsphysicsEntitychemistryEntityCategoriesAtomic physicsGas discharge lampsOptical devices