please answer quicky i will thumb up.

choose all that apply

the equation delta s = c_vln(T_2/T_1)+ R_gas * ln(v_2/v_1) assumes constant specific heat and is derived for ideal gases. this equation..

a) would not be valid for the heat addition step in a brayton cycle

b) would not be valid for a boiler in a rankine cycle

c) can be used to find isentropic relations like T_2/T_1= (v_1/v_2)^k-1

d) can be traced to the first law of thermo