Fission (DP IB Physics: HL): Exam Questions

Which of the following isotopes releases the least amount of potential energy during nuclear fission?

Which statement is correct regarding nuclear fission?

Nuclear reactors use different substances for moderation and for control depending on their ability to absorb neutrons. Some information about commonly used substances:

• Boron and cadmium are good absorbers of neutrons

• Graphite and water are poor absorbers of neutrons

Using this information, which row shows the ideal substances that could be used for controlling and moderating in a nuclear reactor? 

Which statement about nuclear power is incorrect?

In a nuclear reactor, a self-sustained chain reaction is possible because:

I. More neutrons are released in each fission reaction.

II. Every neutron released in a fission reaction immediately initiates a further fission reaction.

III. The fast neutrons are slowed down by the moderator.

Which statements are correct?

Nuclear power stations use a fission reactor to create a nuclear reaction. A nucleus absorbs one neutron, leading to a reaction where more than one neutron is released. These neutrons in turn will set off more reactions in a process called a chain reaction.

Which one of these decay processes would be suitable to create a chain reaction?

A nuclear reaction is given below: 

 ${}_{92}{}^{235}\mathrm{U}+{}_0{}^1\mathrm{n}\to {}_{56}{}^{142}\mathrm{Ba}+{}_{36}{}^{91}\mathrm{Kr}+3{}_0{}^1\mathrm{n}+174.4\mathrm{MeV}$

You may use the following data:

• Mass of ${}_{92}{}^{235}\mathrm{U}$ = 235.0439u

• Mass of  ${}_{56}{}^{142}\mathrm{Ba}$ = 141.9164u

• Mass of ${}_{36}{}^{91}\mathrm{Kr}$ = 90.9234u

• 1u = 931.5 MeV = 1.6610 × 10^–27 kg 

From this data, the mass of a neutron can be inferred as which of the following?

Nucleus N₁ undergoes a fission reaction into nucleus N₂ which undergoes a further fission reaction into nucleus N₃.

The binding energies per nucleon of the three nuclei are E₁, E₂ and E₃ respectively.

Which of the following expressions is correct?

One possible fission reaction of uranium-235 following the capture of a thermal neutron is:

${}_0{}^1\mathrm{n}+{}_{92}{}^{235}\mathrm{U}\to \left[{}_{92}{}^{236}\mathrm{U}\right]\to {}_{40}{}^{98}\mathrm{Zr}+{}_{52}{}^{136}\mathrm{Te}+2{}_0{}^1\mathrm{n}+206\mathrm{MeV}$

Which statement(s) about this reaction is/are correct?

I. The binding energy of the ${}_{92}{}^{236}\mathrm{U}$ nucleus is 206 MeV.

II. The combined rest mass of the fission products equals the rest mass of the ${}_{92}{}^{236}\mathrm{U}$ nucleus.

III. The nucleon number is unchanged by the fission process.