In adiabatic flow with friction, the stagnation temperature along a streamline ____________ (increase / remains constant)

Dry saturated steam enters a friction-less adiabatic nozzle with negligible velocity at a temperature of $${300^ \circ }C.$$ It is expanded to a pressure of $$5000$$ $$kPa.$$ The mass flow rate is $$1$$ $$kg/s$$. Calculate the exit velocity of steam.

One kilomole of an ideal gas is throttled from an initial pressure of $$0.5$$ $$MPa$$ to $$0.1$$ $$MPa.$$ The initial temperature is $$300$$ $$K.$$ The entropy change of the universe is:

Constant pressure lines in the super-heated region of the Mollier diagram will have