Tag: nuclear physics

Questions Related to nuclear physics

Which of the following is a neutron absorber?

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

  1. $Pb$

  2. $Ag$

  3. $Cd$

  4. $Cu$

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Correct Option: C
Explanation:
The purpose of neutron absorber is to have a controlled reaction.
The most important neutron absorber is 10B as 10B4C in control rods, or boric acid as a coolant water additive in PWRs. Other important neutron absorbers that are used in nuclear reactors are xenon, cadmium, hafnium, gadolinium, cobalt etc.

Control rods used in nuclear reactors are made of

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

  1. stainless steel

  2. graphite

  3. cadmium

  4. plutonium

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Correct Option: C
Explanation:

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

For making atom bomb, what else is needed except $U^{235}$?

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

  1. neutron

  2. proton

  3. electron

  4. meson

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Correct Option: A
Explanation:
The fission of $U-235$ in reactors is triggered by the absorption of a low energy neutron, often termed a "slow neutron" or a "thermal neutron". Other fissionable isotopes which can be induced to fission by slow neutrons are plutonium$-239,$ uranium$-233$, and thorium$-232$.

In a nuclear reactor, moderators slow down the neutrons which come out in a fission process.The moderators used have light nuclei. Heavy nuclei will not solve the purpose, because

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

  1. The net weight of the reactor would be unbearably high.

  2. Heavy nuclei will break generating unwanted smaller nuclei.

  3. Elastic collision of neutrons with heavy nuclei will not slow them down.

  4. Substances with heavy nuclei do not occur in liquid or gaseous state at room temperature.

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Correct Option: C

The process by which the percentage of U-235'  in U-238 is increased, is called

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

  1. fission

  2. fusion

  3. chain reaction

  4. enrichment

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Correct Option: D
Explanation:

The process by which the percentage of U-235 in U-238 is increased is called enrichment.

Heavy water is used in nuclear reactor as _________.

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

  1. Coolant

  2. Moderator

  3. Both coolant and moderator

  4. Catalyst

Show answer
Correct Option: C
Explanation:

Both coolant and moderator.

Heary water ( $D _20$ )  also called deuterium oxide, water composed of deuterium, the hydrogen isotope with a mass double that of ordinary hydrogen and oxygen. The heary water is used as a moderator of neutrons and also as a coolent in nuclear power plants.

How many nuclear power plants does India have in 2018?

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

  1. 2

  2. 3

  3. 7

  4. None of these

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Correct Option: C
Explanation:
India has 7 nuclear power plants

India has 22 nuclear reactors in the operation in 7 nuclear power plants, having a total installed capacity of 6780 MW.
List of nuclear power plants
1. Tarapura
operator- NPCIL
Location- Maharashtra
2. Rawatbhata
operator- NPCIL
Location- Rajasthan
3.Kundankulam
operator- NPCIL
Location- Tamil Nadu
4. Kaiga 
operator- NPCIL
Location- Karnataka
5. Kakrapur
operator- NPCIL
Location- Gujrat
6. Kalpakkan
operator- NPCL
Location- Tamil Nadu
7. Narora
operation- NPCIL
Location- Uttar Pradesh

The term $BWR$ stands for

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

  1. Bureau of Workers Rights

  2. Boiling Water Reactor

  3. Bilateral Water Reactor

  4. Bureau of Waste Research

Show answer
Correct Option: B
Explanation:

BWR stands for Boiling Water Reactor.

Most of the highly radioactive 'spent' fuel at nucleus power plant are ___________.

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

  1. shipped abroad

  2. stored in specially designed containers

  3. buried underground

  4. reprocessed for other uses

Show answer
Correct Option: C
Explanation:

Highly radioactive spent fuel at nuclear power plant are buried underground for sake of safety.

What is the importance of moderator in a nuclear reactor?

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

  1. Moderator controls the flow of water inlet.

  2. Controls the nuclear fission by absorbing the excess neutrons.

  3. Controls the nuclear fission by slowing down the neutrons.

  4. None of these

Show answer
Correct Option: C
Explanation:

Controls the nuclear fission by slowing down the neutrons.


A moderator is a material used on a nuclear reactor to slow down the neutrons produced from fission. By slowing down neutrons the probability of a neutron interacting with Uranium-235 nuclei is greatly increased thereby maintaining the chain reaction. Carbon in the form of graphite is commonly used as a moderator.