Discovery of the Proton

Discovery of the Proton MDCAT MCQs with answers

11 past paper MCQs on Discovery of the Proton, from the Atomic Structure unit of MDCAT Chemistry. 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 lightest positive rays are obtained from: (MDCAT 2020)

  1. hydrogen gas
  2. helium
  3. neon
  4. air
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Correct answer: (a) hydrogen gas

The positive ray is an ion of the gas in the tube, and the hydrogen ion is the lightest there is.

2.Which gas in a discharge tube produces the lightest canal ray particles? (MDCAT 2022)

  1. Ar
  2. He
  3. $\mathrm{H_2}$
  4. Ne
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Correct answer: (c) $\mathrm{H_2}$

The positive rays are ions of the gas, and the hydrogen ion, the proton, is the lightest of them.

3.How much heavier is the H-atom as compared to electron? (NUMS MDCAT 2025)

  1. 1937
  2. 1737
  3. 1837
  4. 1637
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Correct answer: (c) 1837

A hydrogen atom is about 1837 times as massive as an electron.

4.Which gas in the discharge tube produces lightest canal ray particles? (UHS MDCAT 2023)

  1. Ar
  2. He
  3. H2
  4. Ne
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Correct answer: (c) H2

Canal rays are positive ions of the gas, and the hydrogen ion is the lightest of all.

5.Mass of electron ___ times smaller than that of proton. (PMC MDCAT 2022)

  1. 1837
  2. 1839
  3. 1836
  4. 1834
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Correct answer: (c) 1836

The proton is about $1836$ times as massive as the electron.

6.In the gaseous phase, when ionization takes place ____________ are isolated and are free from all external influences: (PMC MDCAT 2022)

  1. Atoms and molecule
  2. Atom and cation
  3. Atom and anion
  4. Atom and ion
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Correct answer: (b) Atom and cation

Ionization energy is measured in the gas phase, where an isolated atom gives an isolated cation.

7.Who named the positive rays produced by the hydrogen gas in discharge tube? (PMC MDCAT 2022)

  1. Goldstein
  2. Rutherford
  3. Bohr
  4. Chedwick
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Correct answer: (b) Rutherford

Rutherford identified the positive ray of hydrogen as a new particle and named it the proton.

8.In the discharge tube positive rays moves in which direction (PMC MDCAT 2022)

  1. Towards anode
  2. Towards cathode
  3. Move randomly
  4. Move towards vaccum in the tube
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Correct answer: (b) Towards cathode

Positive rays are cations, so they are drawn to the negative electrode.

9.Proton number of 23Na11 is: (NUMS MDCAT 2022)

  1. 23
  2. 11
  3. 12
  4. 34
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Correct answer: (b) 11

The subscript is the atomic number, so sodium has eleven protons.

10.The mass of electron is: (NUMS MDCAT 2022)

  1. 1836 times more than mass of proton
  2. 1836 times less than mass of proton
  3. 1836 times more than mass of neutron
  4. 1836 times more than mass of hydrogen atom
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Correct answer: (b) 1836 times less than mass of proton

The proton is about $1836$ times as massive as the electron.

11.The e/m values for the positive rays depends on ________enclosed in a discharge tube. (PMC Practice 2021)

  1. Nature of gas
  2. Properties of gas
  3. Composition of gas
  4. All of these
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Correct answer: (a) Nature of gas

A positive ray is an ion of the gas in the tube, so its charge to mass ratio depends on which gas that is.

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