JEE Questions for Physics Atoms And Nuclei Quiz 26 - MCQExams.com

Assertion Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate
Reason According to classical physics all moving electrons radiate
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Radioactive nuclei emit β–1 particles
Reason Electrons exist inside the nucleus
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion ZXA undergoes 2α– decays, 2β– decays and 2γ– decays and the daughter product is Z – 2YA – 8
Reason In α–decay the mass number decreases by 4 and atomic number decreases by 2. In β–decay the mass number remains unchanged, but atomic number increases by 1 only
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Density of all the nuclei is same
Reason Radius of nucleus is directly proportional to the cube root of mass number
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Isobars are the element having same mass number but different atomic number
Reason Neutrons and protons are present inside nucleus
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The force of repulsion between atomic nucleus and α–particle varies with distance according to inverse square law
Reason Rutherford did α–particle scattering experiment
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The positively charged nucleus of an atom has a radius of almost 10–15 m
Reason In α–particle scattering experiment, the distance of closest approach forα–particles is ≃ 10–15m
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic
Reason According to electromagnetic theory an accelerated particle continuously emits radiation
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Electrons in the atom are held due to coulomb forces
Reason The atom is stable only because the centripetal force due to Coulomb\'s law is balanced by the centrifugal force
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The mass of a nucleus can be either less than or more than the sum of the masses of nucleons present in it
Reason The whole mass of the atom is considered in the nucleus
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Hydrogen atom consists of only one electron but its emission spectrum has many lines
Reason Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Atoms and Nuclei-64044.png
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion For the scattering of α–particles at large angles, only the nucleus of the atom is responsible
Reason Nucleus is very heavy in comparison to electrons
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Cobalt-60 is useful in cancer therapy
Reason Cobalt-60 is source of γ–radiations capable of killing cancerous cell
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Amongst alpha, beta and gamma rays, α–particle has maximum penetrating power
Reason The alpha particle is heavier than beta and gamma rays
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The ionizing power of β–particle is less compared to α–particles but their penetrating power is more
Reason The mass of β–particle is less than the mass of α–particle
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The mass of β–particles when they are emitted is higher than the mass of electrons obtained by other means
Reason β–particle and electron, both are similar particle
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Radioactivity of 108 undecayed radioactive nuclei of half life of 50 days is equal to that of 1.2 × 108number of undecayed nuclei of some other material with half life of 60 days
Reason Radioactivity is proportional to half-life
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The binding energy per nucleon, for nuclei with atomic mass number A >100, decreases with A
Reason The nuclear forces are weak for heavier nuclei
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Electron capture occurs more often than positron emission in heavy elements
Reason Heavy elements exhibit radioactivity
  • If both Assertion and reason are true and the Reason is the correct explanation of the assertion.
  • If both Assertion and Reason are true but reason is not the correct explanation of the assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Atoms and Nuclei-64047.png

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  • 2)
    Physics-Atoms and Nuclei-64049.png

  • Physics-Atoms and Nuclei-64050.png

  • Physics-Atoms and Nuclei-64051.png
Which sample contains greater number of nuclei: a 5.00 – µCi sample of 240Pu (half-life 6560y) or a4.45 –µC is ample of 243Am (half-life 7370y)?
  • 240Pu
  • 243Am
  • Equal in both
  • None of these
The energy level diagram for an hydrogen like atom is shown in the figure. The radius of its first Bohr orbit is
Physics-Atoms and Nuclei-64055.png
  • 0.265 Å
  • 0.53 Å
  • 0.132 Å
  • None of these
How much work must be done to pull apart the electron and the proton that make up the Hydrogen atom, if the atom is initially in the state with n = 2?
  • 13.6 × 1.6 × 10–19 J
  • 3.4 × 1.6 × 10–19 J
  • 1.51 × 1.6 × 10–19 J
  • 0
The nuclide 131I is radioactive, with a half-life of 8.04 days. At noon on January 1, the activity of a certain sample is 600Bq. activity at noon on January 24 will be
  • 75Bq
  • Less than 75Bq
  • More than 75Bq
  • 150Bq
U238 decays into Th234 by the emission of an α– particle. There follows a chain of further radioactive decays, either by α– decay or by β – decay. Eventually a stable nuclide is reached and after that, no further radioactive decay is possible. Which of the following stable nuclides is the end product of the U238 radioactive decay chain
  • Pb206
  • Pb207
  • Pb208
  • Pb209
If the mass of a radioactive sample is doubled, theactivity of the sample and the disintegration constant of the sample are respectively
  • Increases, remains the same
  • Decreases, increases
  • Decreases, remains same
  • Increases, decreases

Physics-Atoms and Nuclei-64061.png
  • True
  • False
  • May be true at a particular pressure
  • None of the above
Consider an initially pure `M\' g sample of AX, an isotope that has a half life of T hour. What is it\'s initial decay rate (NA = Avagadro No)?

  • Physics-Atoms and Nuclei-64062.png
  • 2)
    Physics-Atoms and Nuclei-64063.png

  • Physics-Atoms and Nuclei-64064.png

  • Physics-Atoms and Nuclei-64065.png
A hydrogen atom emits a photon corresponding to an electron transition from n = 5 to n = 1. The recoil speed of hydrogen atom is almost (mass of proton 1.6 × 10–27 kg)
  • 10ms–1
  • 2 × 10–2ms–1
  • 4ms–1
  • 8 × 102ms–1
Number of spectral lines in hydrogen atom is.
  • 6
  • 8
  • 15
  • ∝
which of these is a fusion reduction

  • Physics-Atoms and Nuclei-64079.png
  • 2)
    Physics-Atoms and Nuclei-64080.png

  • Physics-Atoms and Nuclei-64081.png
  • None of these
Nucleon is common name for
  • electron and neutron
  • Proton and neutron
  • neutron and Positron
  • neuron and neutrino

Physics-Atoms and Nuclei-64083.png
  • Isotones
  • Isobars
  • Isotope
  • Isomer

Physics-Atoms and Nuclei-64084.png
  • 13.6
  • 3.4 eV
  • 0.85 eV
  • 1.5 eV
A nucleus nXm emit one α - particle and two β - particle. The resulting nucleus is

  • Physics-Atoms and Nuclei-64086.png
  • 2)
    Physics-Atoms and Nuclei-64087.png

  • Physics-Atoms and Nuclei-64088.png

  • Physics-Atoms and Nuclei-64089.png
Which of the following statements are true regarding Bohr\'s model of hydrogen atom?
(I) Orbiting speed of electron decreases as it shifts to discrete orbits away from the nucleus
(II) Radii of allowed orbits of electron are proportional to the principal quantum number
(III) Frequency with which electrons orbit around the nucleus in discrete orbits is inversely proportional to the cube of principal quantum number
(IV) Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbits Select correct answer using the codes given below Codes
  • I and III
  • II and IV
  • I, II and III
  • II, III and IV
In the options given below, let E denote the rest mass energy of a nucleus and n a neutron. The correct option is

  • Physics-Atoms and Nuclei-64093.png
  • 2)
    Physics-Atoms and Nuclei-64094.png

  • Physics-Atoms and Nuclei-64095.png

  • Physics-Atoms and Nuclei-64096.png
Energy released in the fission of a single 92U235 nucleus is 200 MeV. The fission rate of a 92U235 fuelled reactor operating ac a power level of 5 W is
  • 1.56 × 1010s–1
  • 1.56 × 1011s–1
  • 1.56 × 1016s–1
  • 1.56 × 1017s–1
The set which represents the isotope, isobar and isotone respectively is
  • (1H2 , 1H, (79Au197 , 80Hgand (2He3 , 1H2)
  • (2He3 , 1H, (79Au197 , 80Hgand (1H1 , 1H3)
  • (2He3 , 1H, (1H2 , 1Hand (79Au197 , 80Hg
  • (1H2 , 1H, (2He3 , 1Hand (79Au197 , 80Hg198)
  • (1H1 , 1H, (79Au197 , 80Hgand (2He3 , 1H3)
Assume that the nuclear binding energy per nucleon (B /A) versus mass number (A) is as shown in the figure. Use this plot to choose the correct choice (s) given below
Physics-Atoms and Nuclei-64103.png
  • Fusion of two nuclei with mass numbers lying in the range of 1 < A< 50 will release energy
  • Fusion of two nuclei with mass numbers lying in the range of 51 < A < 100 will release energy
  • Fission of a nucleus lying in the mass range of 100 < A< 200 will release energy when broken into two equal fragments
  • Fission of a nucleus lying in the mass range of 200 < A< 260 will release energy when broken into two equal fragments
  • Both (and (4)
The electron in a hydrogen atom makes a transition n1 → n2, where n1 and n2 are the principal quantum numbers of the two states. Assume the Bohr model to be valid. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are
  • n1 = 4, n2 = 2
  • n1 = 8, n2 = 2
  • n1 = 8, n2 = 1
  • n1. = 6, n2 = 3
  • Both (and (4)
Statement I Energy is released when heavy nudei undergo fission or light nuclei undergo fusion
Statement II For heavy nuclei, binding energy per nucleon increases with increasing Z while for light nuclei it decreases with increasing Z.
  • Statement I is true, statements II is true; statement II is a correct explanation for statement I
  • Statement I is true, statement II is true; statements II is not a correct explanation for statement I
  • Statement I is true, statement II is false
  • Statement I is false, statement II is true

Physics-Atoms and Nuclei-64105.png
  • Strong nuclear force acting between the deuterons
  • Coulomb force acting between the deuterons
  • Coulomb force acting between deuteron-electron pairs
  • The high temperature maintained inside the reactor core

Physics-Atoms and Nuclei-64106.png
  • 1.0 × 109 K < T < 2.0 × 109 K
  • 2.0 × 109 K < T < 3.0 × 109 K
  • 3.0 × 109 K < T < 4.0 × 109 K
  • 4.0 × 109 K < T < 5.0 × 109 K

Physics-Atoms and Nuclei-64108.png
  • Deuteron density = 2.0 × 1012 cm–3, confinement time = 5.0 × 10–3 s
  • Deuteron density = 8.0 × 1014 cm–3, confinement time = 9.0 × 10–1 s
  • Deuteron density = 4.0 × 1023 cm–3, confinement time = 1.0 × 10–11 s
  • Deuteron density = 1.0 × 1024 cm–3 cm-3, confinement time = 4.0 × 10–12 s

Physics-Atoms and Nuclei-64110.png
  • a–2
  • a–3/2
  • a–1
  • a2

Physics-Atoms and Nuclei-64112.png
  • 0.8 meV
  • 8 meV
  • 80 meV
  • 800 meV

Physics-Atoms and Nuclei-64114.png
  • n–3/2
  • n–1
  • n1/2
  • n

Physics-Atoms and Nuclei-64116.png

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  • 2)
    Physics-Atoms and Nuclei-64118.png

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  • Physics-Atoms and Nuclei-64120.png
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