Which of the following statements about radiation is true?
a. radiation is the only form of heat transfer that is not experienced on earth.

b. radiation is the only form of heat transfer that can travel through the vacuum of space.

c. radiation is the only form of heat transfer that is experienced on earth.

d. radiation is the only form of heat transfer that is unable to travel through the vacuum of space.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?

The device shows the relative humidity at 22°c. what’s the water vapor density if the maximum water vapor in air at this temperature is 20 grams/cubic meter? a device showing that at 22 degrees celsius the relative humidity is 58%. a. 11.6% b. 11.6 g/m3 c. 12.76% d. 12.76 g/m3 reset next