Apoint source of light is submerged 2.9 m below the surface of a lake and emits rays in all directions. on the surface of the lake, directly above the source, the area illuminated is a circle. what is the maximum radius that this circle could have? take the refraction index of water to be 1.333.

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 is zig zagging a form of acceleration?

In a good thermo flask the main cause of heat loss is