Physics · Science General

Nuclear Physics and Energy

1,296 Questions

Access a comprehensive set of questions on nuclear physics, reactor mechanisms, and atomic energy. Topics include nuclear fission, plasma generation, and radiation control. These physics questions form a core part of the syllabus for various engineering and civil service exams.

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Nuclear Physics and Energy Questions

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

Boron rods, in a nuclear reactor, are used as.

  1. moderator

  2. Protective shield

  3. Coolants

  4. Control rods
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Control rods are used in nuclear reactors to control the fission rate of uranium and plutonium. It is achieved by removing the excess neutrons from the reactor core. The only way to remove the excess neutrons through some elements which posses strong neutron absorption capacity. One such element is boron. By regulating the movement or insertion of boron rods into the reactor core while fission process is in progress, the excess neutrons produced during the chain reaction are absorbed by boron which rods regulate the availability of neutron. 


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

A disadvantage of nuclear power is - 

  1. it produces carbon dioxide which is responsible for global warming

  2. it produces toxic waste

  3. it affects the ozone layer

  4. it requires large amounts of fuel to produce a small amount of energy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nuclear fuels are non-renewable sources of energy and large amount of radioactive materials, which are toxic in nature, are released in the environment which are extremely hazardous to the health of living being for thousands of years.

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

Cadmium rods are used as moderators in a nuclear reactor.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Commonly used moderators include regular(light) water (roughly 75% of the world's reactors), solid graphite (20% of reactors) and heavy water (5% of reactors). Beryllium has also been used in some experimental types, and hydrocarbons have been suggested as another possibility.

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

In a nuclear power plant, uranium atoms

  1. combine and give off heat energy

  2. split and give off heat energy

  3. burn and give off heat energy

  4. split and give off electrons
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A nuclear reactor produces and controls the release of energy from splitting the atoms of Uranium. Nuclear plants do not burn anything to create steam. Instead they split uranium atoms in a process of fission

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

Boron rods are used in nuclear reactor as

  1. moderator

  2. control rods

  3. coolant

  4. protective shield
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Control rods are used in nuclear reactors to control the fission rate of uranium an plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning
The wide absorption spectrum of boron makes it suitable as neutron shield
Multiple choice chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

In a nuclear reactor

  1. the chain reaction is kept under control by rods of cadmium, which reduces the rate

  2. the thick concrete shield is used to slow down the speed of fast neutrons

  3. heavy water (or graphite) moderate the activity of the reactor
  4. out of $U^{238}$ and $U^{235}$ natural uranium has less that 1% of $U^{235}$
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

Heavy water or Graphite are used as coolants and thick concrete shields are used to prevent radiation.

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

The phenomenon of nuclear fission can be carried out both in a controlled and in an uncontrolled way. Out of the following, the correct statements vis-avis these phenomena are

  1. the fission energy released per reaction is much more than conventional nuclear reactions and one of the products of the reaction is that very particle which initiates the reaction

  2. it is the "surface to volume" ratio of the sample of nuclear fuel used which determines whether or not the reaction would sustain itself as a "chain reaction"

  3. the "control rods" in a nuclear reactor must be made of a material that absorbs neutrons effectively

  4. the energy released per fission as well as energy released per unit mass of the fuel in nuclear fission are both greater than the corresponding quantities for nuclear fusion
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Statements (a), (b) and (c) are correct because of following reasons:

$1)$ If nuclear reactions are to be continued, it is necessary that one of the products works for initiating the reaction further.
For example, in the fission $^{235}U$, $3$ neutrons are released which cause fission of further three $^{235}U$ atoms.
$2)$ There are certain value of surface to volume ratio of the sample of nuclear fuel used which should be satisfied so as the fission can occur.
$3)$ Basically, the fission is continuously carried out due to production of neutrons.
In order to control the reaction, the neutrons should be absorbed.