Composition of the Atomic Nucleus

Composition of the Atomic Nucleus MDCAT MCQs with answers

13 past paper MCQs on Composition of the Atomic Nucleus, from the Nuclear Physics unit of MDCAT Physics. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.The protons in the nucleus of an atom DO NOT exit due to (UHS MDCAT 2025)

  1. Electromagnetic force
  2. Gravitational Force
  3. Weak Nuclear Force
  4. Strong Nuclear Force
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Correct answer: (b) Gravitational Force

Gravitation between protons is far too feeble to matter; it is the strong nuclear force that holds them.

2.Mass number A refers to _____ (KMU MDCAT 2024)

  1. Number of electrons
  2. Number of nucleons
  3. Number of neutrons
  4. Number of protons
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Correct answer: (b) Number of nucleons

The mass number counts the protons and neutrons together, that is the nucleons.

3.For two down quarks total charge is: (PMC MDCAT 2022)

  1. -2/3 e
  2. -2 e
  3. -1 e
  4. -1/2 e
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Correct answer: (a) -2/3 e

A down quark carries $-\tfrac13e$, so two of them carry $-\tfrac23e$.

4.Naturally occuring fusion reaction source Is: (PMC MDCAT 2022)

  1. Moon
  2. Sun
  3. Earth
  4. satellite
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Correct answer: (b) Sun

Hydrogen fusing to helium is what keeps the Sun shining.

5.How many up quarks in proton: (PMC MDCAT 2022)

  1. 1
  2. 2
  3. 3
  4. 4
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Correct answer: (b) 2

A proton is two up quarks and one down quark.

6.Which particle has no charge (PMC MDCAT 2022)

  1. Electrons
  2. Proton
  3. Neutron
  4. Positron
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Correct answer: (c) Neutron

The neutron carries no charge.

7.The total mass of protium deuterium and tritium is _______ more than three H atoms. (PMC Practice 2021)

  1. 3 neutrons
  2. 3 protons
  3. 3 electrons
  4. None of these
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Correct answer: (a) 3 neutrons

Deuterium carries one neutron and tritium two, so the three together have three more than three protium atoms.

8.Mass and energy are related to each other by: (PMC Practice 2021)

  1. Newton's law
  2. Einstein's law
  3. Coulomb's law
  4. All of these options are correct
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Correct answer: (b) Einstein's law

Einstein’s relation $E=mc^2$ ties mass to energy.

9.According to Einstein, mass and energy are: (PMC Practice 2021)

  1. Inversely proportional
  2. Directly proportional
  3. Equal to each other
  4. None of these options is correct
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Correct answer: (b) Directly proportional

$E=mc^2$ makes the energy proportional to the mass.

10.The nuclear forces are considered as? (PMC Practice 2021)

  1. Strong force
  2. Weak force
  3. Electromagnetic force
  4. All of these options are correct
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Correct answer: (a) Strong force

The nucleons are held by the strong nuclear force.

11.Heavy nucleus of atoms go through fission so that they can: (UHS MDCAT 2019)

  1. absorb low amount of energy
  2. absorb high amount of energy
  3. reduce their binding energy nucleon
  4. increase their binding energy per nucleon
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Correct answer: (d) increase their binding energy per nucleon

The fragments lie nearer the peak of the binding energy curve, and the difference is released.

12.What is the quark composition of a Proton? (UHS MDCAT 2019)

  1. Two up quarks and one down quark
  2. Two up quarks and one strange quark
  3. One up quark and two strange quarks
  4. Two down quarks and one up quark
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Correct answer: (a) Two up quarks and one down quark

A proton is two up quarks and one down quark.

13.What is the name of the energy which is released when an atom is formed from its constituent particles? (UHS MDCAT 2018)

  1. Atomic Energy
  2. Radioactive Energy
  3. Nuclear Energy
  4. Binding Energy
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Correct answer: (d) Binding Energy

The energy released when the nucleons come together is the binding energy.

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