The Nucleus

The mass of a neutral carbon atom in ground state is

• exact 12u

• less than 12u

• more than 12u

• depends on the form of carbon such as graphite or charcoal

The mass number of a nucleus is equal to

• the number of neutrons in the nucleus

• the number of protons in the nucleus

• the number of nucleons in the nucleus

• none of them

As compared to C-12 atom, C-14 atom has

• two extra protons and two extra electrons

• two extra protons but no extra electron

• two extra neutrons and two extra electrons

• two extra neutrons and no extra electrons

The mass number of a nucleus is

• always less than its atomic number

• always more than its atomic number

• equal to its atomic number

• sometimes more than and sometimes eual to its atomic number

The graph of ln(R/Ro) versus ln A (R=radius of a nucleus and A= mass number) is

• a straight line

• a parabola

• an ellipse

• none of them

Let F_pp,F_pn and F_nn denote the magnitudes of the nuclear force by a proton on a proton,by a proton on a neutron and by a neutron on a neutron respectively. When the separation is 1fm,

• F_pp>F_pn=F_nn

• F_pp=F_pn=F_nn

• F_pp>F_pn>F_nn

• F_pp<F_pn=F_nn

Two protons are kept at a separation of 10nm. Let F_n and F_e be the nuclear force and the electromagnetic force between them.

• F_n =F_e

• F_e >> F_n

• F_e <<F_n

• F_n and F_e differ only slightly.

Which of the following is a wrong description of binding energy of a nucleus?

• It is the energy required to break a nucleus into its constituent nucleons.

• It is the energy made available when free nucleons combine to form a nucleus.

• It is the sum of the rest mass energies of its nucleons minus the rest mass energy of the nucleus.

• It is the sum of the kinetic energy of all the nucleons in the nucleus.

As the mass number increases, which of the following quantities related to a nucleus do not change?

• Mass

• Volume

• density

• binding energy

Let F_pp,F_pn and F_nn denote the magnitudes of the net force by a proton on a proton,by a proton on a neutron and by a neutron on a neutron respectively. Neglect gravitational force.When the separation is 1fm,

• F_pp>F_pn=F_nn

• F_pp=F_pn=F_nn

• F_pp>F_pn>F_nn

• F_pp<F_pn=F_nn