Question 13 (2 points) Given the following images, choose the one that most likely represents an M-class star. (2 points)
A
B
с
D
Оа
A
Oь в
Ос
О с с
Od D

answer; i believe that the correct answer is (a) potassium(k)

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.