cientists often have to deal with numbers that are either very large or very small. For example, the radius of the Sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. Express each number in an alternate form.

the answer is option a.

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.