Assuming the face PQRS to be at uniform temperature, its steady state temp is

Question

For the three dimensional object shown in the fig below. Five faces are insulated. The sixth face (PQRS), which is not insulated, interacts thermally with the ambient, with a convective heat transfer coefficient of 10W/m²K. the ambient temperature id 30⁰C. heat is uniformly generated inside the object at the rate of 100W/m³, assuming the face PQRS to be at uniform temperature, its steady state temp is                                                                                                                                               

 

      (a) 10C                           (b) 20C                        (c) 30C                           (d) 40C