The variation of temperature with position in a wall is show

The variation of temperature with position in a wall is shown below for a specifies time, t_i during a transient (time-varying) process. Is the wall being heated or cooled? Explain why?

Solution

The graph depicts the temperature variation across the wall. The inside wall is at higher temperature and the out side wall is at a lower temperature. The temperature decreases with increasing value of x

The heat flow rate is q = k A dT/ s where k is the thermal conductivity of the wall, A - is the ares of the wall, dT is the temperature between inside and outside wall and s - is the thickness of the wall.

So the inside wall is heated as the graph says, the temperature decreases as we go towards the outer surface of the wall