State second law of thermodynamics in different ways.

(i) It is impossible to convert heat completely into an equivalent amount of work without producing some change in some other part of the system.
(ii) All natural and spontaneous processes take place in one direction only and are thermodynamically irreversible.
(iii) It is impossible to convert heat from a reservoir into work by a cyclic process without transferring to a colder reservoir.
(iv) Heat cannot pass itself from a colder to a hotter body.
(v) It is impossible for a self-acting machine, unaided by any external agency, to convey heat from a body at lower temperature to a body at a higher temperature.