Ateacher used a geiger-muller(gm)tube to measure the background radiation in her laboratory.
she rest the counter to zero, waited one minute and then took the count reading. she then repeated the same procedure two more times.
the results are as follows,
count after one minute-15
-24
-18
the readings here are correct.
why are the readings different?

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

The air that we breath is made mostly of which gaseous molecule

What are some properties of transverse waves?