Tag: nuclear physics

Quizzes (6) Questions (198)

Questions Related to nuclear physics

Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

During a nuclear fission reaction 

  1. a heavy nucleus breaks into two fragments by itself

  2. a light nucleus bombared by thermal neutrons breaks up

  3. a heavy nucleus bombared by thermal neutrons breaks up

  4. two light nuclei combine to give a heavier nucleus and possibly other products
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In nuclear physics and nuclear chemistry, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts, and reaction is triggered by neutron bombardment.
Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

The fissionable material used in a breeder reactor is ________

  1. $ _{92}\textrm{U}^{235}$
  2. $ _{94}\textrm{Pu}^{239}$
  3. $ _{90}\textrm{Th}^{234}$
  4. $ _{c}\textrm{C}^{12}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Non-fissionable uranium-238 is 140 times more abundant than the fissionable U-235 and can be efficiently converted into Pu-239 by the neutrons from a fission chain reaction.

Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

The critical mass of $U^{235}$ can be reduced by 

  1. putting a neutron reflector around it

  2. heating it

  3. mixing impurity in it

  4. putting neutron absorber around it
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Surrounding a spherical critical mass with a neutron reflector further reduces the mass needed for criticality. A common material for a neutron reflector is beryllium metal. This reduces the number of neutrons which escape the fissile material, resulting in increased reactivity.
Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

The most suitable material for moderator in a nuclear reactor is 

  1. $D _{2}$
  2. $Cd$
  3. $B$
  4. $ _{92}\textrm{U}^{235}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In nuclear reactor, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction.
Commonly used moderators include regular (light) water (roughly 75% of the world's reactors), solid graphite (20% of reactors) and heavy water.
Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

The fission of $U^{238}$ is possible by 

  1. only fast neutrons

  2. only slow neutrons

  3. fast as well as slow neutrons

  4. fast protons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Uranium-23, do not usually undergo fission when struck by slow neutrons, but do split when struck with neutrons of high enough energy. The fast neutrons produced in a hydrogen bomb by fusion of deuterium and tritium have even higher energy than the fast neutrons produced in a nuclear reactor. This makes it possible to increase the yield of any given fusion weapon by the simple expedient of adding layers of cheap natural (or even depleted) uranium. Fast fission of uranium-238 provides a large part of the explosive yield, and fallout, in many designs of hydrogen bomb.