The figure show a cross-section of a double glass unit of a window on a vertical wall. A graph wall. A graph of the temperature at different points within the unit is show next to it. The temperature difference across the unit is `13 K`. It has a crossp-sectional area of `1.3 m^(2)` and the rate of heat flow through it is `65 W`. Then the correct statement is (Glass has a thermal conductivity of `1 W m^(-1) K^(-1)`)

Options

A. The unit is in steady state and in thermal equilibrium
B. The unit is in steady state but not in thermal equalibrium.
C. The unit is not in steady state but is in thermal
D. The unit neither in steady state nor in thermal equilibrium

Answer

B

Explanation

Temperature is not same every where so unit is not in thermal equilibrium but heat is flowing at constant rate.