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

The sources of energy obtained in a nuclear reaction are :

  1. Mass defect

  2. Binding energy

  3. Fission

  4. Fusion

  5. All of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In fusion a heavy nucleus is splitted into two nuclei of comparable masses. The mass of parent nucleus is greater than the total mass of daughter nuclei, some mass is disappeared, this is mass defect and this mass appeared as the binding energy.

In fusion two or more than two light nuclei fuse together to form a heavy nucleus. The sum of masses of light nuclei is greater than the total mass of heavy nucleus, some mass is disappeared, this is mass defect and this mass appeared as the binding energy.

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

Nuclear power stations are usually located near source of water because.

  1. Fuel could be transported to the station by ships

  2. Chemical wastes are discharged into the river

  3. Water is used as coolant and moderator

  4. Water is used to rotate the turbines of the generator
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Water can be used as coolant and moderator

Nuclear power stations are usually located near water source because water is used as coolant and moderator. 

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

The control rod in a nuclear reactor is made of.

  1. Cadmium

  2. Uranium

  3. Graphite

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

Control rods are used in nuclear reactors to control the fision rate of uranium and plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning.

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

In a nuclear reactor the excess reactivity can be controlled by using _____________ rods.

  1. Lead rods

  2. Iron rods

  3. Uranium rods

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

Lead rods 

In nuclear reactor the lead rods have the ability to control the excess reactivity by suitably absorbing the neutrons and thus making the reaction controllable. 

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

Cadmium rods are used in a nuclear reactor

  1. To produce neutrons

  2. To speed up neutrons

  3. To absorb neutrons

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

To absorb neutrons 

Cadmium rods are inserted in nuclear reacter to absorb the extra nucleons any keep the nuclear reaction ratio of  1:1 , also keep the reaction stable. Cadmium has a high thermal neutron absorption cross section. Therefore cadmium rods will absorb neutrons, making them unavailable to cause fission.

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

In a nuclear reactor heavy water is used as a.

  1. Moderate

  2. Fuel

  3. Shield

  4. Controlling element
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Moderator 

A neutron moderator is a modium that reduces the spread of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving U-235. Heavy water is used as a moderator in nuclear reactor.

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

Moderator is a substance that ..................... the neutrons in a nuclear reactor.

  1. Slow down

  2. Activates

  3. Both (a) and (b) above

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A moderator is a material used in nuclear reactors to reduce the speed of fast neutrons, thereby increasing the probability of them causing further fission in U-235 nuclei.

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

The amount of $U^{235}$ to be fissioned, to operate a $10\ kW$ nuclear reactor is (Approximately)

  1. $1.2 \times 10 ^ { - 5 }\ \mathrm { gm } / \mathrm { s }$
  2. $1.2 \times 10 ^ { - 7 }\ \mathrm { gm } / \mathrm { s }$
  3. $1.2 \times 10 ^ { - 9 }\ \mathrm { gm } / \mathrm { s }$
  4. $1.2 \times 10 ^ { - 11 }\ \mathrm { gm } / \mathrm { s }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Using the relation P = (n * E) / t, where P is power, n is number of fissions, and E is energy per fission. 10 kW = 10,000 J/s. E = 200 MeV = 200 * 1.6 * 10^-13 J. Calculating the mass of U-235 required leads to approximately 1.2 * 10^-11 g/s.

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
Cadmium rods are used in a nuclear reactor for regulating the power level of the reactor. Cadmium rods are used in nuclear reactors to control the fission rate of radioactive material used. It is capable of absorbing many neutrons without fissioning themselves.
Heavy water, graphite etc. are used as moderator