Consider the following statements pertaining to heat transfer through fins
(i) They must be arranged at right angles to the direction of flow of working fluid
(ii) The temperature along the fin is variable and accordingly heat transfer rate varies along the fin elements
(iii) Fins are equally effective irrespective whether they are on the hot side or cold side of the fluid
(iv) Fins are made of materials that have thermal conductivity higher than that of wall
Identify the correct statements