A closed system of ideal gas undergoes a complete cyclic process and returns to its initial state. Which statement correctly describes the change in internal energy ΔU for the entire cycle?
a) ΔU equals the net work done by the gas during the cycle.
b) ΔU depends on the path taken and varies with the specific processes in the cycle.
c) ΔU=0 because internal energy depends only on the state of the system.
d) ΔU is zero only for isothermal cycles; otherwise it is non-zero.