What is voltage?

a. it is the sum of the electrical potential energy in two places in an electric field.

b. it is the flow of an electric charge in only one direction.

c. it is the difference in electrical potential energy between two places in an electric field.

d. it is the flow of an electric charge that regularly reverses direction.

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

Explain vector addition, triangle method and parallelogram method

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.