Exam 30: Nuclear Physics

The radioactivity due to carbon-14 measured in a piece of a wooden casket from an ancient burial site is found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produces 160 counts per minute. The half-life of carbon-14, a beta-minus emitter, is 5730 years. What would we calculate for the age of the artifact, assuming that the activity for living wood has remained constant over time?

The radius R of a nucleus of mass number A is given by R = R₀ A^1/3, where R₀ = 1.2 × 10^-15 m, calculate the density of a nucleus that has contains 57 protons and 82 neutrons. The mass of a nucleon (proton or neutron) is 1.67 × 10^-27 kg.

Name the first three isotopes of hydrogen, write their symbols in standard notation, and indicate which one is the most common and which one is the most unstable.

In β^- decay, the number of neutrons in the nucleus is

What happens to the half-life of a radioactive substance as it decays?

A fusion reaction releases energy because the binding energy of the resulting nucleus

Inside the nucleus, the weakest of the four fundamental forces is

Bismuth $^{212}_{83}$ Bi is known to be radioactive. The stability of $\^{212} _{83}$ Bi with respect to alpha, beta-plus and beta-minus decay is to be determined. The following atomic masses are known: $^{4}_{2}$ He: 4.002603 u $^{208} _{81}$ Tl: 207.981998 u $^{212} _{82}$ Pb: 211.991871 u $^{212}_{83}$ Bi: 211.991255 u $^{212}_{84} Po$ : 211.988842 u The $^{212}_{83} Bi$ nucleus is

The proton is made up of which one of the following quark combinations (up, down, strange, charm, top, bottom)?

The primary reason that very large nuclei are unstable is due to

When a stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle, the energy released in the process is 5.24 MeV. The following masses are known: $^{4}_{2}$ He: 4.002603 u $^{235}_{92}$ U: 235.043924 u What is the kinetic energy of the $^{235}_{92}$ U nucleus? (1 u = 931.5 MeV/c²)

In positron decay, the number of protons in the nucleus is

The decay rate of a radioactive sample decreases from 175 kBq to 12.4 kBq in 18.3 s. What is the half-life of this sample?

Which of the following particles are not made up of quarks? (There could be more than one correct choice.)

In a $^{93}_{41}$ Nb nucleus, how many protons, neutrons, and electrons are found there?

An oxygen-15 nucleus, $^{15}_{8}$ O, decays to another atomic nucleus by emitting a β⁺ ray. What is the other atomic nucleus?

Leptons can interact by which of the following forces?

Determine the missing product X in the following nuclear reaction: $^{13}_{7}$ N + neutron → X + alpha particle

What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.)

The atom ⁴⁰K decays radioactively to the gas ⁴⁰Ar. An ancient rock is found to contain enough ⁴⁰Ar gas to indicate that 77.0% of the ⁴⁰K in the rock has decayed to ⁴⁰Ar since the rock solidified. (Any previous argon would have boiled out of liquid rock.) How long ago did the rock solidify? The half-life of ⁴⁰K is 1.25 billion years.