(1) Where P (watts) is the radiated power from a body of area A (m2) at temperature T (K). Îµ is emissivity, a dimensionless number between 0 and 1 that determines the. efficiency of a body to radiate and absorb energy. A perfect radiator and absorber has an emissivity of 1. Soil, ice, rock, asphalt and human skin have emissivities slightly less than 1. Ï -8is the Stefan-Boltzmann constant, 5.67 x10 Wm-2T-4 T is the body temperature in Kelvin. So if absolute temperature (in Kelvin degrees) doubles, radiated power increases by a factor of sixteen. Also, changes in temperature alter radiation peak wavelengths. Temperature increases move peak radiation to smaller wavelengths and vice-versa. Equilibrium and Solid Angles
Martin Luther King was often seen wearing a gold Rolex DayDate at many of his speaking functions. Musician John Mayer is seen here wearing his Rolex Daytona. Talk show host Ellen DeGeneres also wears a Rolex Daytona. Actor Brad Pitt is often seen wearing a Rolex Explorer.
Ellen DeGeneres. Ellen Lee DeGeneres (/dáµ»ËdÊÉnÉráµ»s/; born January 26, 1958) is an American comedian, television host, actress, writer, and producer. DeGeneres starred in the popular sitcom Ellen from 1994 to 1998 and has hosted her syndicated TV talk show, The Ellen DeGeneres Show, since 2003. Her stand-up career started in the early 1980s, culminating in a 1986 appearance on The Tonight Show Starring Johnny Carson.