Question

Absorb Incident radiant onorgy Reflected Emitted Absorbed Retained Black Black Incident radiant energy Reflected Emitte Retained Absorbed Silver coated Silver coated A person with a surface area of 1.20 m2, and a skin temperature of 27 °C, is in a room that is at a temperature of 17.6 °C. The emissivity of the skin is 0.895, The Stefan-Boltzmann constant is 5.67 x 10-8 W/(m2K). (a) How much energy is radiated by the person in 1 minute? Keep 2 decimal places. Enter a number J Submit (5 attempts remaining) (b) How much energy is absorbed by the person from the surroundings in 1 minute? Keep 2 decimal places. Enter a number Submit (5 attempts remaining)

Answer 1

que surface area of Sшка адая 4 редки - 12ом Temperature of skin= 210 = 27+273 = 3ook Emissivity of skin (8) = 0.895 stefan Boltzmann constant o= seotx 10 Energy radiated by person in a mennite (60 sec) E = Erty a AXT E = AxtErTY - 1.2ox (60 sec ) x 0,895x5 678 10? X1300) 4 - 29,595.38 Joule Energy absorbed by person ofsom surroundings in 1 min Temperature of sussounding To= 1766°c 273+1706 = 29016k Axt E 1.20x60x0,89585067x158 (290164 E 150205229 2605 6.7 97 Joule

Joule net Energy loss in I minule - E-E 29,595.358- 26,056.797 = 3,538.561 Joule power of light bult = 100w P = Energy = 100W Emissivity &= 1.0 tume surface area = 7x105m - EOTY Axt AX EO = 14 100 7x105x1x 5.678108 (25.1954 10 12) 4 = 1 2.24x103 Kelvin-T Temperature = 2,240141K in °C = (-9,240.41-273) °C = 1967,42 °C