Scientists & Inventions

1. Who among the following is known as the Father of Nuclear Physics ?

Who among the following is known as the Father of Nuclear Physics ?

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E. Rutherford
J.J. Thomson
Niels Bohr
James Chadwick
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Ernest Rutherford (E. Rutherford) is widely regarded as the “Father of Nuclear Physics”. His experiments, particularly the gold foil experiment, led to the discovery of the atomic nucleus and the idea that the atom is mostly empty space. He also coined the terms “alpha” and “beta” rays, discovered the proton, and performed the first artificial nuclear transmutation.
Rutherford’s work revolutionized the understanding of atomic structure and radioactivity.
J.J. Thomson discovered the electron.
Niels Bohr developed an early model of the atom based on quantum mechanics.
James Chadwick discovered the neutron.
Rutherford received the Nobel Prize in Chemistry in 1908 for his investigations into the disintegration of the elements, and the chemistry of radioactive substances.

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2. Which one among the following statements is not correct?

Which one among the following statements is not correct?

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Johannes Kepler proved that the path of each planet around the Sun is elliptical with the Sun at its focus.
The first successful attempt to establish the size of the Earth is credited to Eratosthenes.
The first Greek to profess a Sun-centred or Heliocentric Universe was Sir Isaac Newton.
The famous astronomical book Almagest was compiled by Ptolemy.
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The correct option is C) The first Greek to profess a Sun-centred or Heliocentric Universe was Sir Isaac Newton.
Statement A is correct. Johannes Kepler formulated his laws of planetary motion in the early 17th century, including the first law stating that planets orbit the Sun in elliptical paths with the Sun at one focus.
Statement B is correct. Eratosthenes of Cyrene, a Greek scholar in the 3rd century BC, is famous for making the first relatively accurate calculation of the Earth’s circumference using geometry and astronomical observations.
Statement C is incorrect. The first known Greek astronomer to propose a heliocentric model of the solar system was Aristarchus of Samos in the 3rd century BC, predating Kepler and Newton by over a thousand years. Sir Isaac Newton (1643-1727) was a British physicist and mathematician, not Greek, and his work explained *why* planetary orbits are elliptical (gravity), building upon Kepler’s descriptive laws.
Statement D is correct. The Almagest is the 2nd-century AD astronomical treatise by Claudius Ptolemy, which presented a detailed geocentric model of the universe that remained the standard view for centuries.
Aristarchus’s heliocentric model was not widely accepted in antiquity, with the geocentric model of Aristotle and later Ptolemy dominating astronomical thought until the Copernican revolution in the 16th century.

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3. Electron was discovered by

Electron was discovered by

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Michael Faraday
Joseph John Thomson
Henry Cavendish
Earnest Rutherford
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UPSC CISF-AC-EXE – 2017
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The electron was discovered by Joseph John Thomson.
J.J. Thomson discovered the electron in 1897 through his experiments with cathode ray tubes, determining that cathode rays were composed of negatively charged particles much smaller than atoms.
Michael Faraday contributed significantly to electromagnetism and electrochemistry. Henry Cavendish discovered hydrogen and determined the composition of water. Ernest Rutherford conducted the gold foil experiment leading to the discovery of the atomic nucleus and later discovered the proton.

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4. Who among the following has coined the term ‘Quark’, the fundamental p

Who among the following has coined the term ‘Quark’, the fundamental particles that make up protons and neutrons in an atomic nucleus ?

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Richard Feynman
Murray Gell-Mann
Albert Einstein
Niels Bohr
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The term ‘Quark’ for the fundamental particles that make up protons and neutrons was coined by American physicist Murray Gell-Mann in 1964. He proposed the quark model independently of George Zweig, who had called the particles “aces”. Gell-Mann chose the name “quark” from James Joyce’s novel “Finnegans Wake”.
Murray Gell-Mann proposed the quark model and named these fundamental particles ‘quarks’.
Protons and neutrons are baryons, which are composed of three quarks. For example, a proton is made of two up quarks and one down quark (uud), and a neutron is made of one up quark and two down quarks (udd).

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5. Who among the following are awarded with the Special Breakthrough Priz

Who among the following are awarded with the Special Breakthrough Prize in Fundamental Physics for the year 2017 ?

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Stephen W Hawking and Roger Penrose
Ronald Drever, Kip S Thorne and Rainer Weiss
Joseph Polchinski, Andrew Strominger and Cumrun Vafa
J Michael Kosterlitz, Duncan Haldane and David J Thouless
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UPSC CAPF – 2017
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The Special Breakthrough Prize in Fundamental Physics for the year 2017 was awarded to the LIGO scientific collaboration for the observation of gravitational waves. The key individuals representing the collaboration were Ronald Drever, Kip S Thorne, and Rainer Weiss, who were pioneers in the development of the LIGO project.
The prize recognized the detection of gravitational waves, a prediction of Einstein’s general theory of relativity, which opened a new window for observing the universe. Drever, Thorne, and Weiss are considered founding figures of the LIGO experiment.
The 2016 Nobel Prize in Physics was also awarded for this discovery, specifically to Rainer Weiss, Barry C. Barish, and Kip S. Thorne. Ronald Drever had passed away earlier in 2017. The Breakthrough Prize in Fundamental Physics is one of the Breakthrough Prizes founded by Sergey Brin, Priscilla Chan and Mark Zuckerberg, Yuri and Julia Milner, and Anne Wojcicki.

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6. The name of the particle ‘Boson’ is associated with the name of

The name of the particle ‘Boson’ is associated with the name of

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J.C. Bose
S.N. Bose
Isaac Newton
Albert Einstein
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The name of the particle ‘Boson’ is associated with the name of S.N. Bose.
The term ‘Boson’ is named after the Indian physicist Satyendra Nath Bose (S.N. Bose) for his work on quantum statistics, which laid the foundation for describing the behavior of these particles.
Satyendra Nath Bose collaborated with Albert Einstein, and their joint work led to the development of the Bose-Einstein statistics and the prediction of the Bose-Einstein condensate. Particles that obey Bose-Einstein statistics are called bosons.

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7. Neutrons were discovered by

Neutrons were discovered by

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James Chadwick
Ernest Rutherford
J. J. Thomson
John Dalton
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The correct answer is (A) James Chadwick. James Chadwick discovered the neutron in 1932.
The discovery of the neutron completed the basic understanding of the composition of the atomic nucleus, alongside protons.
J. J. Thomson discovered the electron in 1897. Ernest Rutherford, through the gold foil experiment, discovered the atomic nucleus and later identified protons within the nucleus (in 1917-1919). John Dalton is credited with developing the modern atomic theory in the early 19th century.

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8. Name the scientist who first used a glass prism to obtain the spectrum

Name the scientist who first used a glass prism to obtain the spectrum of sunlight

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C. V. Raman
Lord Rayleigh
Isaac Newton
S. Chandrasekhar
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The correct answer is (C) Isaac Newton. Sir Isaac Newton was the first scientist to use a glass prism to split sunlight into its constituent colors, demonstrating that white light is a spectrum of colors.
Newton’s experiments with prisms laid the foundation for the understanding of the dispersion of light and the nature of color.
C. V. Raman was an Indian physicist known for his work on the scattering of light (Raman effect). Lord Rayleigh was a British physicist who made significant contributions to physics, including work on scattering (Rayleigh scattering). S. Chandrasekhar was an Indian-American astrophysicist known for his theoretical work on the evolution of stars.

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9. Which one of the following scientists mentioned that an electron in an

Which one of the following scientists mentioned that an electron in an atom could revolve in certain stable orbits without the emission of radiant energy ?

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Ernest Rutherford
J.J. Thomson
Niels Bohr
Albert Einstein
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UPSC NDA-1 – 2024
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Niels Bohr proposed a model of the atom in 1913 to explain the stability of atoms and the emission spectra of elements like hydrogen. One of his key postulates was that electrons orbit the nucleus in certain specific, stable orbits (also called stationary states) without emitting electromagnetic radiation. This addressed the problem in Rutherford’s model, where orbiting electrons were expected to lose energy continuously and spiral into the nucleus according to classical electromagnetism.
– Rutherford’s model suggested electrons orbit the nucleus but didn’t explain atomic stability.
– Classical physics predicted orbiting electrons would radiate energy and spiral into the nucleus.
– Niels Bohr proposed quantized orbits where electrons do not radiate energy, leading to stable atoms.
J.J. Thomson discovered the electron and proposed the plum pudding model. Ernest Rutherford conducted the gold foil experiment, leading to the discovery of the atomic nucleus and the nuclear model. Albert Einstein contributed significantly to physics, including the theory of relativity and the photoelectric effect, but the specific postulate about stable electron orbits without radiation is attributed to Bohr.

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10. Equal volume of all gases, when measured at the same temperature and p

Equal volume of all gases, when measured at the same temperature and pressure, contain an equal number of particles. Who proposed the above law ?

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Charles
Boyle
Avogadro
Lussac
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UPSC NDA-1 – 2023
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The law stating that equal volumes of all gases, at the same temperature and pressure, contain the same number of molecules is known as Avogadro’s Law. It was proposed by Italian scientist Amedeo Avogadro in 1811. This law is a key principle in chemistry and relates the volume of a gas to the number of moles (and thus the number of particles) present.
Avogadro’s Law relates the volume of a gas to the number of particles (molecules or atoms) under constant temperature and pressure conditions.
Boyle’s Law relates pressure and volume (at constant temperature and number of particles). Charles’s Law relates volume and temperature (at constant pressure and number of particles). Gay-Lussac’s Law relates pressure and temperature (at constant volume and number of particles). These laws, along with Avogadro’s Law, combine to form the ideal gas law (PV = nRT).

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