What is the main point of the passage? Select one:

a.
Van Gogh was the most famous painter of the Impressionist era.

b.
Art conservationists can always restore art.

c.
Artists’ paints can eventually damage the canvasses.

d.
Ultraviolet rays can cause chemical reactions.

Please help D:

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

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.