Thermodynamics

Q$-1(20$ pts$.)$ Three Carnot cycles are operated as follows

a$)(5$p$)$ A Carnot engine operates between $30C$ and $300C.$ Calculate its thermal efficiency

b$)(5$p$)$ A Carnot refrigerator engine operates between $-5C$ and $35C.$ Calculate its COP R

c$)(5$ p$)$ A Carnot heat pump operates between $-5C$ and $35C($same as above refrigerator$).$ Calculate its COP

d$)(5$p$)$ Check for the parts $($b$)$ and $($c$)$ if the condition COP.