Exam 29: Nuclear Physics

The unstable isotope ²³⁴Th decays by β emission with a half-life of 24.5 days.If the initial decay rate of the sample is 6.2 × $10^{17}$ Bq,what is the decay rate after 37 days?

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

Fermium-253 has a half-life of 3.00 days.If a sample of fermium originally has 7.37 × $10^7$ nuclei,how long will it take for there to be only 3.36 × $10^6$ fermium-253 nuclei left in this sample?

Rutherfordium-261 has a half-life of 1.08 min.What is the decay constant of rutherfordium-261 in terms of seconds?

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

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

In the nuclear reaction ${}^{3}_{1}$ H + ${}^{3}_{1}$ H → X + ${}^{4}_{2}$ He,what is X?

In the first nuclear reaction observed,physicists saw an alpha particle (Z = 2)interact with a nitrogen nucleus in air (Z = 7)to produce a proton.The energy of the alpha particle was $55 \mathrm { MeV } \text {, }$ enough to enable the nuclei to touch in spite of the Coulomb repulsion.What distance (in fm)between the centers of the alpha particle and the nitrogen was reached? This determines a limit on the radius of the nitrogen nucleus.(1 eV = 1.60 × 10^-19 J,e = 1.60 × 10^-19 C,1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

In the nuclear reaction 16 8 O + ${}^{4}_{2}$ He → X + ${}^{19}_{10}$ Ne,what is X?

Determine the missing product X in the following nuclear reaction: $^{235} _{92} U$ + neutron → 141 56 Ba + X + 3 neutrons

The binding energy per nucleon of a nucleus

What happens to the half-life of a radioactive substance as we increase its temperature?

When a β⁺ particle is emitted from an unstable nucleus,the atomic number of the nucleus

The main fuel for producing energy in the center of the sun is

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

Consider the fusion reaction: ${}^{2}_{1}$ H + ${}^{2}_{1}$ H + ${}^{2}_{1}$ H → ${}^{4}_{2}$ He + ${}^{1}_{1}$ H + ${}^{1}_{0}$ n The know atomic masses are ${}^{2}_{1}$ H: 2.01410 u ${}^{4}_{2}$ He: 4.00260 u 1 1 H: 1.00783 u ${}^{1}_{0}$ n: 1.008665 u where 1 u = 1.6605 × 10-27 kg.What mass of deuterium fuel, ${}^{2}_{1}$ H,is used up in producing $5.6 \times 10^{15} \mathrm {~J}$ of energy by this reaction?

Rubidium ${}^{87}_{37}$ Rb is a naturally occurring isotope that undergoes β^- decay.What isotope is the product of this decay?

The isotope 235 92 U is radioactive and decays in a series to 227 90 Th.In this series,the particles ejected from the nucleus are

The energy radiated by a star,such as the sun,results chiefly from

An old bone sample contains 321 g of carbon and has an activity of 947 decays/min due to the carbon-14 in it.The half-life of carbon-14 is 5730 y.Assume that the activity of the atmospheric carbon is,and has remained,0.255 Bq per gram of carbon. (a)How old is the sample? (b)What will be the activity of the sample 2000 y from now,in decays per minute?