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**1. A solid cylinder of radius r1 = 2.3 cm, length h1 = 4.2 cm, emissivity 0.88, and temperature 24°C is suspended in an environment of temperature 55°C. (a) What is the cylinder's net thermal radiation transfer rate P1? (b) If the cylinder is stretched until its radius is r2 = 0.52 cm, its net thermal radiation transfer rate becomes P2. What is the ratio P2/P1?**

**2. P1 = ([tex]\sigma[/tex]) ([tex]\epsilon[/tex]) A1(T**

A1 = 2([tex]\pi[/tex]) r1

_{env}^{4}- T^{4})A1 = 2([tex]\pi[/tex]) r1

^{2}+ 2 ([tex]\pi[/tex]) r h**3. A1 = 9.393362*10**

P1 = (5.67*10

^{-3}m^{2}P1 = (5.67*10

^{-8})(.88)(9.393362*10^{-3})((273+55)^{4}-(273+24)^{4})) = 1.77WI have (b) .. but for some reason (a) is wrong.. here is answer for (b) [tex]\frac{P2}{P1}[/tex] =

**2.87**

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