the effect of ultraviolet radiation in lowering the sparking voltage across a spark gap: an example of photoelectric effect.
noun, Physics. 1. an electromagnetic wave produced by oscillations in an electric circuit, as a radio or radar wave: first investigated by H. R. Hertz. noun 1. an electromagnetic wave with a frequency in the range from about 3 × 1010 hertz to about 1.5 × 105 hertz
[Dutch her-tsawkh] /Dutch ˈhɛr tsɔx/ noun 1. James Barry Munnik [mœn-uh k] /ˈmœn ək/ (Show IPA). South African statesman and general: prime minister 1924–39. /ˈhɜːtsɒɡ/ noun 1. James Barry Munnik. 1866–1942, South African statesman; prime minister (1924–39): founded the Nationalist Party (1913), advocating complete South African independence from Britain; opposed South African participation in World […]
/Danish hɛrdsbrɔŋ/ noun 1. Ejnar (ˈəɪnar). 1873–1967, Danish astronomer: he discovered the existence of giant and dwarf stars, originating one form of the Hertzsprung-Russell diagram Hertzsprung (hěrts’sprng) Danish astronomer who specialized in photographing the stars and introduced the concept of absolute magnitude. Hertzsprung also demonstrated the relationship between the surface temperature of stars and their […]
- Hertzsprung-Russell diagram
[hairt-sproo ng-ruhs-uh l] /ˈhɛərt sprʊŋˈrʌs əl/ noun, Astronomy. 1. the graph showing the absolute magnitude plotted against the surface temperature for a group of stars. /ˈhɜːtssprʌŋˈrʌsəl/ noun 1. a graph in which the spectral types of stars are plotted against their absolute magnitudes. Stars fall into different groupings in different parts of the graph See […]