Which has a bigger surface area, powder or marble chips

powder

Explanation:

Between the powder and marble chips, the powder will have a larger surface area.

For the same masses of a solid substance in different forms such as lump, granules or powder, the smaller particle size of each form the larger the surface area.

Surface area increases from lumps to granules and them powder

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.