Tag: chemistry

Questions Related to chemistry

The man-made element which was made in the nuclear reactor is

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

  1. polonium

  2. plutonium

  3. thorium

  4. uranium

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Correct Option: B
Explanation:

The man-made element which was made in the nuclear reactor is plutonium. Polonium, thorium and uranium are naturally find in the nature.

In nuclear reactor, Cadmium rods are used as

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

  1. Fuel

  2. Moderator

  3. Control Rods

  4. None

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Correct Option: C
Explanation:

Cadmium, Boron and Steel rods are used as control rods in a nuclear reactor.
Commonly moderators are Heavy water, graphite and Beryllium and Berillium oride.
Common fuels are Uranium $(^{238}U)$, enriched Uranium $(^{235}U)$ and plutonium $(^{236}{Pu})$ and $^{232}{Th}$

The material used to slow the neutrons in a reactor is called

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

  1. Control rod

  2. Moderator

  3. Fuel

  4. Heat exchanger

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Correct Option: B
Explanation:

The function of a moderator is to slow down the fast moving neutrons.
The function of control rod is to absorb (capture) the neutrons.

Nuclear fission is caused by :

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

  1. Fast protons

  2. Fast neutrons

  3. Slow protons

  4. Slow neutrons

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Correct Option: D
Explanation:

Nuclear fission is caused by both fast and slow neutrons.

The fuel used in nuclear power plants is

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

  1. U-235

  2. U-238

  3. U-236

  4. None of the above

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Correct Option: A
Explanation:

The fuel in nuclear power plant is U-235 Uranium-235 Is an isotope of Uranium making up about 0.72% of natural uranium. It is the only fissile isotope with a primordial nuclide found in significant quantity in nature.

The first atomic reactor was made by 

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

  1. $Fermi$

  2. $Bohr$

  3. $Taylor$

  4. $Rutherford$

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Correct Option: A
Explanation:
The first man-made self-sustaining nuclear chain reaction was initiated in  on 2 December 1942, under the supervision of Enrico Fermi.

Boron rods in a nuclear reactor are used to 

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

  1. absorb excess neutrons

  2. absorb alpha particle

  3. slow down the reaction

  4. speed up the reaction

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Correct Option: A
Explanation:
When a neutron collides with the uranium atom, then energy is released along with three more neutrons which further collide with another uranium atom an so the chain reaction continues. Thus boron rods in nuclear reactor are used to absorb excess neutrons so that the reaction rate remains under control.  

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$-232$.