in a Carnot cycle, air is used with constant specific heats. The maximum pressure is $18$ bar and the maximum temperature is $410$C$.$ The compression ratio during isentropic compression is $6,$ and during isothermal expansion, it is $1\mathrm{.}5.$ The following calculations are requested:

a$)$ Temperature at the beginning of the isothermal compression

b$)$ Heat input

c$)$ Pressure at the end of the isothermal expansion

d$)$ Pressure at the beginning of the isothermal compression

e$)$ Exergy destroyed during this cycle