50 questions · timed · auto-graded
Which of the following atoms has the lowest ionization potential
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(a) |
(b) |
(c) |
(d) |
(c) 
Assertion : For the scattering of a-particles at a large angles, only the nucleus of the atom is responsible.
Reason : Nucleus is very heavy in comparison to electrons.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.
The Bohr model of atoms
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(a) Assumes that the angular momentum of electrons is quantized |
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(b) Uses Einstein’s photo-electric equation |
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(c) Predicts continuous emission spectra for atoms |
| (d) Predicts the same emission spectra for all types of atoms |
(a) Assumes that the angular momentum of electrons is quantized
On the bombardment of neutron with Boron. a-particle is emitted and product nuclei formed is
|
(a) |
(b) |
(c) |
(d) |
(c) 
During the nuclear fusion reaction
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(a) A heavy nucleus breaks into two fragments by itself |
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(b) A light nucleus bombarded by thermal neutrons breaks up |
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(c) A heavy nucleus bombarded by thermal neutrons breaks up |
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(d) Two light nuclei combine to give a heavier nucleus and possibly other products |
(d) Two light nuclei combine to give a heavier nucleus and possibly other products
The binding energy per nucleon is maximum in the case of
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(a) |
(b) |
(c) |
(d) |
(b) 
Isotopes are atoms having
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(a) Same number of protons but different number of neutrons |
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(b) Same number of neutrons but different number of protons |
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(c) Same number of protons and neutrons |
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(d) None of the above |
(a) Same number of protons but different number of neutrons
Heavy water is
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(a) Water at 4 ℃ |
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(b) Compound of deuterium and oxygen |
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(c) Compound of heavy oxygen and heavy hydrogen |
| (d) Water, in which soap does not lather |
(b) Compound of deuterium and oxygen
As the electron in Bohr orbit of Hydrogen atom passes from state n = 2 to n = 1, the kinetic energy K and potential energy U change as
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(a) K two-fold, U four-fold |
(b) K four-fold, U two-fold |
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(c) K four-fold, U also four-fold |
(d) K two-fold, U also two-fold |
(c) K four-fold, U also four-fold
The example of nuclear fusion is
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(a) Formation of Ba and Kr from U235 |
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(b) Formation of He from H |
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(c) Formation of Pu – 235 from U - 235 |
| (d) Formation of water from hydrogen and oxygen |
(b) Formation of He from H
Fission of nuclei is possible because the binding energy per nucleon in them
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(a) Increases with mass number at high mass numbers |
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(b) Decreases with mass number at high mass numbers |
| (c) Increases with mass number at low mass numbers |
| (d) Decreases with mass number at low mass numbers |
(b) Decreases with mass number at high mass numbers
nucleus after absorbing energy decays into two α - particles and an unknown nucleus. The unknown nucleus is
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(a) Nitrogen |
(b) Carbon |
(c) Boron |
(d) Oxygen |
(b) Carbon
A free neutron decays into a proton, an electron and
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(a) A neutrino |
(b) An antineutrino |
(c) An alpha particle |
(d) A beta particle |
(b) An antineutrino
In a nuclear reaction, which of the following is conserved
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(a) Atomic number |
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(b) Mass number |
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(c) Atomic number, mass number and energy |
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(d) None of these |
(c) Atomic number, mass number and energy
energy. The emitted particle is
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(a) Neutron |
(b) Proton |
(c) α - particle |
(d) Neutrino |
(c) α - particle
Nuclear fission experiments show that the neutrons split the uranium nuclei into two fragments of about same size. This process is accompanied by the emission of several
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(a) Protons and positrons |
(b) a - particles |
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(c) Neutrons |
(d) Protons and a-particles |
(c) Neutrons
When neutrons are bombarded on nucleus of 
, the number of emitted neutrons will be
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(a) 1 |
(b) 2 |
(c) 3 |
(d) 4 |
(c) 3
In the nuclear reaction 
what does X stand for
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(a) An electron |
(b) A proton |
(c) A neutron |
(d) A neutrino |
(d) A neutrino
In nuclear fission, the fission reactions proceeds with a projectile. Which of the following suits the best
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(a) Slow proton |
(b) Fast neutron |
(c) Slow neutron |
(d) None of these |
(c) Slow neutron
A chain reaction is continuous due to
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(a) Large mass defect |
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(b) Large energy |
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(c) Production of more neutrons in fission |
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(d) None of these |
(c) Production of more neutrons in fission
γ-rays radiation can be used to create electron-positron pair. In this process of pair production, γ-rays energy cannot be less than
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(a) 5.0 MeV |
(b) 4.02 MeV |
(c) 15.0 MeV |
(d) 1.02 MeV |
(d) 1.02 MeV
Fast neutrons can easily be slowed down by
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(a) The use of lead shielding |
(b) Passing them through water |
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(c) Elastic collisions with heavy nuclei |
(d) Applying a strong electric field |
(b) Passing them through water
What was the fissionable material used in bomb dropped at Nagasaki (Japan) in the year 1945 ?
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(a) Uranium |
(b) Nepturium |
(c) Berkalium |
(d) Plutonium |
(d) Plutonium
The main source of solar energy is
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(a) Fission reactions |
(b) Fusion reactions |
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(c) Chemical reactions |
(d) Combustion reactions |
(b) Fusion reactions
Atom bomb consists of two pieces of and a source of
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(a) Proton |
(b) Neutron |
(c) Meson |
(d) Electron |
(b) Neutron
Fusion reaction is initiated with the help of
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(a) Low temperature |
(b) High temperature |
(c) Neutrons |
(d) Any particle |
(b) High temperature
In nuclear reaction 
A denotes
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(a) Electron |
(b) Positron |
(c) Proton |
(d) Neutron |
(d) Neutron
The explosion of the atomic bomb takes place due to
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(a) Nuclear fission |
(b) Nuclear fusion |
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(c) Scattering |
(d) Thermionic emission |
(b) Nuclear fusion
The control rod in a nuclear reactor is made of
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(a) Uranium |
(b) Cadmium |
(c) Graphite |
(d) Plutonium |
(b) Cadmium
In helium nucleus, there are
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(a) 2 protons and 2 electrons |
(b) 2 neutrons, 2 protons and 2 electrons |
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(c) 2 protons and 2 neutrons |
(d) 2 positrons and 2 protons |
(c) 2 protons and 2 neutrons
For a nucleus to be stable, the correct relation between neutron number N and Proton number Z is
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(a) N > Z |
(b) N = Z |
(c) N < Z |
(d) N ≥ Z |
(d) N ≥ Z
The force acting between proton and proton inside the nucleus is
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(a) Coulombic |
(b) Nuclear |
(c) Both |
(d) None of these |
(c) Both
Atomic number of a nucleus is Z and atomic mass is M. The number of neutron is
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(a) M - Z |
(b) M |
(c) Z |
(d) M + Z |
(a) M - Z
Antiparticle of electron is
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(a) |
(b) |
(c) Positron |
(d) Neutrino |
(c) Positron
The mass of a neutron is the same as that of
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(a) A proton |
(b) A meson |
(c) An epsilon |
(d) An electron |
(a) A proton
Nucleus of an atom whose atomic mass is 24 consists of
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(a) 11 electrons, 11 protons and 13 neutrons |
(b) 11 electrons, 13 protons and 11 neutrons |
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(c) 11 protons and 13 neutrons |
(d) 11 protons and 13 electrons |
(c) 11 protons and 13 neutrons
Which of the following has the mass closest in value to that of the positron (1 a.m.u = 931 Mev)
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(a) Proton |
(b) Electron |
(c) Photon |
(d) Neutrino |
(b) Electron
Outside a nucleus
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(a) Neutron is stable |
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(b) Proton and neutron both are stable |
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(c) Neutron is unstable |
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(d) Neither neutron nor proton is stable |
(c) Neutron is unstable
Binding energy of a nucleus is
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(a) Energy given to its nucleus during its formation |
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(b) Total mass of nucleus converted to energy units |
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(c) Loss of energy from the nucleus during its formation |
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(d) Total K.E. and P.E. of the nucleons in the nucleus |
(c) Loss of energy from the nucleus during its formation
The average binding energy per nucleon in the nucleus of an atom is approximately
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(a) 8 eV |
(b) 8 KeV |
(c) 8 MeV |
(d) 8 J |
(c) 8 MeV
In 
nucleus, there are
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(a) 138 protons and 88 neutrons |
(b) 138 neutrons and 88 protons |
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(c) 226 protons and 88 electrons |
(d) 226 neutrons and 138 electrons |
(b) 138 neutrons and 88 protons
The masses of neutron and proton are 1.0087 a.m.u. and 1.0073 a.m.u. respectively. If the neutrons and protons combine to form a helium nucleus (alpha particles) of mass 4.0015 a.m.u. The binding energy of the helium nucleus will be (1 a.m.u.= 931 MeV)
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(a) 28.4 MeV |
(b) 20.8 MeV |
(c) 27.3 MeV |
(d) 14.2 MeV |
(a) 28.4 MeV
The mass defect for the nucleus of helium is 0.0303 a.m.u. What is the binding energy per nucleon for helium in MeV
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(a) 28 |
(b) 7 |
(c) 4 |
(d) 1 |
(b) 7
The neutron was discovered by
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(a) Marie Curie |
(b) Pierre Curie |
(c) James Chadwick |
(d) Rutherford |
(c) James Chadwick
Which of the following particles are constituents of the nucleus
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(a) Protons and electrons |
(b) Protons and neutrons |
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(c) Neutrons and electrons |
(d) Neutrons and positrons |
(b) Protons and neutrons
If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of 
is
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(a) 122.4 eV |
(b) 30.6 eV |
(c) 13.6 eV |
(d) 3.4 eV |
(b) 30.6 eV
Which of the following transition will have highest emission wavelength
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(a) n = 2 to n = 1 |
(b) n = 1 to n = 2 |
(c) n = 2 to n= 5 |
(d) n = 5 to n = 2 |
(d) n = 5 to n = 2
The de-Broglie wavelength of an electron in the first Bohr orbit is
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(a) Equal to one fourth the circumference of the first orbit |
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(b) Equal to half the circumference of the first orbit |
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(c) Equal to twice the circumference of the first orbit |
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(d) Equal to the circumference of the first orbit |
(d) Equal to the circumference of the first orbit
The first member of the Paschen series in hydrogen spectrum is of wavelength 18,800 Å. The short wavelengths limit of Paschen series is
|
(a) 1215 Å |
(b) 6560 Å |
(c) 8225 Å |
(d) 12850 Å |
(c) 8225 Å
Whenever a hydrogen atom emits a photon in the Balmer series
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(a) It need not emit any more photon |
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(b) It may emit another photon in the Paschen series |
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(c) It must emit another photon in the Lyman series |
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(d) It may emit another photon in the Balmer series |
(c) It must emit another photon in the Lyman series
