If the substance in the diagram was heated to T2, what is happening if the substance is allowed to approach T1? 1.The average kinetic energy is decreasing
2. The average kinetic energy has increased
3. The highest energy level has decreased
4. Fewer molecules would have a lower energy level
5. More molecules have a higher energy level

Answer is in the file below

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answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.