Which of the following describes an atomic property that makes some atoms useful for nuclear medicine applications and nuclear power generation? A.
Isotopes of an atom differ in the number of electrons they contain. Some isotopes are stable, and these are used in nuclear medicine and the generation of nuclear power.

B.
Isotopes of an atom differ in the number of neutrons they contain. Some isotopes are unstable, and these are used in nuclear medicine and the generation of nuclear power.

C.
Isotopes of an atom differ in the number of neutrons they contain. Some isotopes are stable, and these are used in nuclear medicine and the generation of nuclear power.

D.
Isotopes of an atom differ in the number of electrons they contain. Some isotopes are unstable, and these are used in nuclear medicine and the generation of nuclear power.

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole

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.