The temperature of a piece of copper with a mass of 95.4 grams increases from 74°c to 99°c as the metal absorbs 849 J of energy

gas

explanation:

smoke is the matter of a gas

the answer is 0.42 is that is an option. this question provides no info

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.