Loren has the samples of elements that are listed below at room temperature. he exposes the samples to the same heat source until each sample reaches a temperature of 90.0°c. 10 g of al(s) (c subscript p. = 0.897 j/(gi°c)) 10 g of ag(s) (c subscript p.= 0.234 j/gi°c ) 10 g of fe(s) (c subscript p. = 0.450 j/gi°c) 10 g of zn(s) (c subscript p. = 0.387 j/gi°c ) from first to last, which lists the order in which these samples will reach 90.0°c?

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.