A solid cylinder of radius r1 = 3.0 cm, length h1 = 6.0 cm, emissivity 0.87, and temperature 35°C is suspended in an environment of temperature 64°C.
(a) What is the cylinder's net thermal radiation transfer rate P1?
(b) If the cylinder is stretched until its radius is r2 = 0.42 cm, its net thermal radiation transfer rate becomes P2. What is the ratio P2/P1?