How much energy would be required to break a helium nucleus into its constituents, two protons and two neutrons? The rest masses of a proton (including an electron), a neutron, and helium are, respectively, 1.00783 u, 1.00867 u, and 4.00260 u. (This energy difference is called the total binding energy of the $\frac{4}{2}$He nucleus.)

a. Is a nucleus visible in each blood cell? Are nuclei apparent in white blood cells? b. The shape of the nucleus is often used to subclassify a leukocyte. What variation do you see in the shape of nuclei in leukocytes? c. What is the ratio of leukocytes to erythrocytes? d. Do frog blood cells have nuclei?

The hydrogen atom is composed of one proton in the nucleus and one electron, which moves about the nucleus. In the quantum theory of atomic structure, it is assumed that the electron does not move in a well-defined orbit. Instead, it occupies a state known as an orbital, which may be thought of as a “cloud” of negative charge surrounding the nucleus. At the state of lowest energy, called the ground state, or 1s-orbital, the shape of this cloud is assumed to be a sphere centered at the nucleus. This sphere is described in terms of the probability density function p(r)=4/a^30 r^2 e^-2r/a0, r≥0 where a0 is the Bohr radius (a0 ≈ 5.59 × 10^-11m). The integral P(r) = ^r∫0 4/a^30 s^2 e^-2s/a0 ds gives the probability that the electron will be found within the sphere of radius r meters centered at the nucleus. Find lim r→∞ p(r). For what value of r does p(r) have its maximum value?

Is it possible for a hydrogen nucleus to emit an alpha particle? Why? (a) yes, because alpha particles are the simplest form of radiation, (b) no, because it would require the nuclear fission of hydrogen, which is impossible, (c) yes, but it does not occur very frequently, (d) no, because the nucleus does not contain enough nucleons.

Match the subatomic particles (1 to 3) to the descriptions: surround the nucleus

1. protons 2. neutrons 3. electrons

A nitrogen isotope, ${ }_{7}^{12} \mathrm{N}$, has a nuclear mass of 12.0188 u. a. What is the binding energy per nucleon? b. Does it require more energy to separate a nucleon from a ${ }_{7}^{14} \mathrm{N}$ nucleus or from a ${ }_{7}^{12} \mathrm{N}$ nucleus? ${ }_{7}^{14} \mathrm{N}$ has a mass of 14.00307 u.

Explain the following Sherlock Holmes saying in terms of conditional probability, carefully distinguishing between prior and posterior probabilities: “It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.”

The mass of a proton is about 1.7 x 10$^{-24}$ g. The mass of a neutron is about the same as a proton. The nucleus of an atom of carbon has 6 protons and 6 neutrons. The mass of the nucleus is about 2 x 10$^{-26}$ units. Circle the best choice for the units this measurement is given in: g/kg/tons.

Hereditary information is stored inside the (1) ribosomes, which have chromosomes that contain many genes (2) ribosomes, which have genes that contain many chromosomes (3) nucleus, which has chromosomes that contain many genes (4) nucleus, which has genes that contain many chromosomes

What do the nucleus, ER, ribosomes, Golgi apparatus, and vesicles work together to do? holder and protector of DNA ___________________

Suppose a marble with a radius of $1.2 \mathrm{~cm}$ has the density of a nucleus, as given in Example. What is the mass of this marble?

How much energy must an $\alpha$ particle have to just "touch" the surface of a ${ }_{92}^{238} \mathrm{U}$ nucleus?

Normally, we disregard the magnetic moment of the nucleus. In what application does the nuclear magnetic moment become important?

Calculate the order of magnitude of the shift in energy of a (a) $1 \mathrm{eV}$ photon and (b) $1 \mathrm{MeV}$ photon resulting from the recoil of an iron nucleus. Do this by first calculating the momentum of the photon and then by calculating $p^2 / 2 \mathrm{~m}$ for the nucleus using that value of momentum. Compare with the natural line width calculated