Transient heating of a concrete wall. a wall made of concrete 0.305 m thick is insulated on the rear side. the wall at a uniforin temperature of 10°c (283.2 k) is exposed on the front side to a gas at 843°c (1116.2 k). the convection coefficient is 28.4 w/m².k, the thermal diffusivity is 1.74 x 10" mº/h, and the thermal conductivity is 0.935 w/ m k . (a) calculate the time for the temperature at the insulated face to reach 232°c (505.2 k). (b) calculate the temperature at a point 0.152 m below the surface at this same time.

The image compares the arrangement of electrons in two different neutral atoms. a figure labeled atom q has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has six black spheres. to the left of this figure is another figure labeled atom p. atom p has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has seven black spheres. which of the following best explains the position of the two atoms in the periodic table?