Answer:
The thermal power emitted by the body is [tex]P_t = 286.8 \ Wm^{-2}[/tex]
The net power radiated is  [tex]P_{net} = 460 \ W[/tex]
Explanation:
From the question we are told that
  The length of the assumed hum[tex]T_{room} = 20 ^oC[/tex]an body is  L =  2.0 m
  The circumference of the assumed human body is  [tex]C = 0.8 \ m[/tex]
  The  Stefan-Boltzmann constant is  [tex]\sigma = 5.67 * 10^{-8 } \ W\cdot m^{-2} \cdot K^{-4}.[/tex]
  The temperature of skin [tex]T_{body} = 30^oC[/tex]
   The temperature of the room is Â
  The emissivity is  e=0.6
The thermal power radiated by the body is mathematically represented as
      [tex]P_t = e * \sigma * T_{body}^4[/tex]
substituting value
    [tex]P_t = 0.6 * 5.67*10^{-8} * (303)^4[/tex]
    [tex]P_t = 286.8 \ Wm^{-2}[/tex]
The net power radiated by the body is mathematically evaluated as
  [tex]P_{net} = P_t * A[/tex]
Where A is the surface area of the body which is mathematically evaluated as
   [tex]A = C* L[/tex]
substituting values
   [tex]A = 0.8 * 2[/tex]
   [tex]A = 1.6 m^2[/tex]
=> Â Â [tex]P_{net} = 286.8 * 1.6[/tex]
=> Â [tex]P_{net} = 460 \ W[/tex]
