Heinrich Rudolf Hertz (22 February 1857 - 1 January 1894) was a German physicist who clarified and expanded James Clerk Maxwell's electromagnetic theory of light, which was first demonstrated by David Edward Hughes using non-rigorous  trial and error procedures.. 
A tún mọ̀ sí Jwáong.Ìtọ́kasí àwọn amòyeàwọn ara Korea gúúsù.. 