A ray of light is passing from air into glass. If the angle of incidence, with respect to the normal to the interface, is increased: a. Total internal reflection will occur when the angle of incidence equals the critical angle
b. Total internal reflection will occur when the angle of incidence is less than the critical angle
c. Total internal reflection will occur when the angle of incidence is greater than the critical angle
d. Angle of refraction will increase but there will be no total internal reflection

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)