Heat transfer

PLEASE COULD YOU PROVIDE AN EXPLINATION WITH THE RIGHT ANSWER??

note my answer ( layer one ) was incorrect

THANKS!

The schematic below shows the temperature profile in a composite wall, consisting of three layers of equal thickness. If we want to improve the insulating capacity of the wall, which layer should be made thicker? T. 1 | 2 | 3 N2 T Layer 1 Layer 3 Layer 2 Increasing the thickness does not improve the insulating capacity