Which of the following statements is accurate? a. compressions and rarefactions occur throughout a transverse wave. b. the wavelength of both transverse and longitudinal waves is measured parallel to the direction of the travel of the wave. c. amplitude of longitudinal waves is measured at right angles to the direction of the travel of the wave and represents the maximum distance the molecule has moved from its normal position. d. sound waves passing through the air will do so as transverse waves, which vibrate vertically and still retain their horizontal positions.

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

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.

How are positive ions different from neutral atoms