Star A has a radius of 200 000 km and a surface temperature of 6 000 K.Star B has a radius of 400 000 km and a surface temperature of 3 000 K.The emissivity of both stars is the same.What is the ratio of the rate of energy radiated by Star A to that of Star B?
A styrofoam container used as a picnic cooler contains a block of ice at 0C.If 225 grams of ice melts in 1 hour,how much heat energy per second is passing through the walls of the container? (The heat of fusion of ice is 3.33 105 J/kg).
One mole of helium gas expands adiabatically from 2 atm pressure to 1 atm pressure.If the original temperature of the gas is 20C,what is the final temperature of the gas? ( = 1.67)
Air expands adiabatically (no heat in,no heat out)from T = 300 K and P = 100 atm to a final pressure of 1 atm.Treat the gas as ideal with = 1.4,and determine the final temperature.Compare your result to the boiling points of nitrogen (77.4 K)and oxygen (90.2 K).Could this method result in the liquification of air?