Indicate whether each statement about the nucleus of an atom is true or false. The nucleus of an atom is neutral. The nucleus of an atom contains only neutrons. The number of nucleons present in the nucleus is equal to the number of electrons present outside the nucleus. The nucleus accounts for almost all the volume of an atom. The nucleus accounts for almost all the mass of an atom. The nucleus can be positively or negatively charged depending on the identity of the atom.

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons

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.