Atomic structure

41.Atoms or group of atoms which are electrically charged are known:
 
A. Anions
 
B. Cations
 
C. Ions
 
D. Atoms
 
Option “D” is correct.
Ions, any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged ions are called cations; negatively charged ions, anions.
42.Electron was discovered BY
 
A. Thomson
 
B. Neil Bohr
 
C. Rutherford
 
D. Faraday
 
Option “A” is correct.
43.Who discovered the proton?
 
A. Rutherford
 
B. Chadwick
 
C. Thomson
 
D. Faraday
 
Option “A” is correct.
44.Which of the following was discovered by James Chadwick?
 
A. electron
 
B. Proton
 
C. neutrons
 
D. mason
 
Option “C” is correct.
In 1932, J. Chadwick discovered another subatomic particle which had no charge and a mass nearly equal to that of a proton. It was eventually named as a neutron.
Neutrons are present in the nucleus of all atoms, except hydrogen.
In general, a neutron is represented as ‘n’.
45.The particles that display dual nature of both waves and particles are :
 
A. meson
 
B. Proton
 
C. electron
 
D. neutron
 
Option “C” is correct.

Electron has dual nature in it. It acts as a particle when you try to explain the photoelectric effect. While trying to explain diffraction and polarization we consider it has wave nature.
Initially, people considered electron to have only particle nature. But, they could not explain experimental observations like difraction. If we consider electron to be completely having wave nature, we cannot explain experimental observations like photoelectric effect. So the only reasonable solution was that electron possessed both particle and wave nature.

46.Who is the discoverer of positron?
 
A. Chadwick
 
B. Yukawa
 
C. Anderson
 
D. Rutherford
 
Option “C” is correct.
By studying the tracks of cosmic ray particles in a cloud chamber, in 1932 Carl Anderson discovered a positively-charged particle with a mass seemingly equal to that of an electron. Anderson’s particle was the first antiparticle proven by experiment and was named a “positron”.
47.Who discovered the atomic nucleus?
 
A. Rutherford
 
B. Dalton
 
C. Einstein
 
D. Thomson
 
Option “A” is correct.
Ernest Rutherford discovered the nucleus of the atom in 1911.
48.An Indian scientist whose name is associated with a particle of a specific origin
 
A. CV Raman
 
B. Satyendra Nath Bose
 
C. Chandrashekhar
 
D. Saha
 
Option “B” is correct.
It was Indian physicist Satyendra Nath Bose after whom class of subatomic particles ‘Boson’ is named. The elusive Higgs Boson is one of the Bosons.
49.The name of the scientist who discovered neutron is-
 
A. Chadwick
 
B. Bohr
 
C. Fermi
 
D. Rutherford
 
Option “A” is correct.
In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron. Chadwick was born in1891 in Manchester, England.
50.Which of the following atom has no neutron in its nucleus ?
 
A. lithium
 
B. lithium
 
C. protium
 
D. helium
 
Option “B” is correct.

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