Test: Transient Heat Conduction - 2 - Chemical Engineering MCQ

In a lumped parameter model, the temperature variation with time is

One dimensional unsteady state heat transfer equation for a sphere with heat generation at the rate q can be written

Transient three-dimensional heat conduction is governed by ONE of the following differential equations (α - thermal diffusivity, k - thermal conductivity and ψ - volumetric rate of heat generation)

Steady two-dimensional heat conduction takes place in the body shown in the figure below. The normal temperature gradients over surface Pand Q can be considered to be uniform. The temperature gradient  at surface Q is equal to 10 K/m. Surface Pand Q are maintained at constant temperatures as shown in the figure, while the remaining part of the boundary is insulated. The body has a constant thermal conductivity of 0.1 W/mK. The value and   at surface P are 

A large concrete slab 1 m thick has one dimensional temperature distribution:
T = 4 - 10x + 20x² + 10x³
where T is temperature and x is distance from one face towards other face of wail. If the slab material has thermal diffusivity of 2 x 10^-3m²/hr, what is the rate of change of temperature at the other face of the wall?