Mastering physics 12.68. Answer is not 259 or 260. It is also not in Kelvin If y
ID: 1480290 • Letter: M
Question
Mastering physics 12.68. Answer is not 259 or 260. It is also not in Kelvin
If you lie on the ground at night with no cover, you get cold rather quickly. Much of this is due to energy loss by radiation. At night in a dry climate, the temperature of the sky can drop to -40 degree C. If you are lying on the ground with thin clothing that provides little insulation, the surface temperature of your skin and clothes will be about 30 degree C. Estimate the net rate at which your body loses energy by radiation to the night sky under these conditions.Explanation / Answer
the rate of energy loss is given by
Q1 = sigma (T14)
rate of absorption of energy is given by
Q2 = sigma (T24)
net rate
Q =Q1-Q2
Q = siigma( T14 -T24)
sigma = 5.67 x 10-8 units
T1 = 30 degrees = 303.15 K
T2 = -40 degrees = 233.15 K
plugging in we get
Q = 311.3 Joules/sec