The system loses 'q' amount of heat though no work is done on the system. What type of wall does the system have?

Explanation

Here heat is transferred through a thermally conducting walls.
In this case charge in internal energy `triangle=q`
can be measured interms of temperature difference.
`q=T_(B)-T_(A)`
Here no work is done at constant volume.
q=+ve -heat transferred from surrounding to system.
q=- ve -heat transferred from system to surrounding.