JEE Questions for Physics Atoms And Nuclei Quiz 20 - MCQExams.com

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 for α-particles is ≈ 10-15 m.
  • 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 Balmer series lies in the visible region of electromagnetic spectrum.
Physics-Atoms and Nuclei-63573.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-particle 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 Cobalr-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 ionising 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 particles.
  • 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 It is not possible to use 35Cl as the fuel for fusion energy.
ReasonThe binding energy of 35Cl is too small.
  • 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.
Why high temperature is required for fusion reaction?
  • At high temperature, kinetic energy is sufficient to overcome repulsive force
  • Atoms are ionized at high temperature
  • Molecules break up at high temperature
  • Nuclei break up at high temperature
Assertion Neutrons penetrate matter more readily as compared to protons.
Reason Neutrons are slightly more massive than protrons
  • 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 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 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 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.
Assertion Radioactivity of 108 undecayed radioactive nuclei of half life of 50 days is equal to that of 1.2 x 108 number 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.
In the Bohr\'s hydrogen atom model, the radius of the stationary orbit is directly proportional to (n = principal quantum number)
  • n–1
  • n
  • n–2
  • n2

Physics-Atoms and Nuclei-63581.png
  • 10.2 eV
  • 12.1 eV
  • 13.6 eV
  • 3.4 eV
An electron has a mass of 9.1 × 10–31 kg. It revolvesaround the nucleus in a circular orbit of radius 0.529 × 10–10 metre at a speed of 2.2 × 106 m/s. The magnitude of its linear momentum in this motion is
  • 1.1 × 10–34kg - m/s
  • 2.0 × 10–24 kg - m/s
  • 4.0 × 10–24 kg - m/s
  • 4.0 × 10–31 kg - m/s
In a Rutherford scattering experiment when a projectile of charge z1 and mass M1 approaches a target nucleus of charge z2 and mass M2, the distance of closest approach is r0. The energy of the projectile is
  • Directly proportional to M1× M2
  • Directly proportional to z1z2
  • Inversely proportional to z1
  • Directly proportional to mass M1
Ionization potential of hydrogen atom is 13.6 V. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. The spectral lines emitted by hydrogen atoms according to Bohr\'s theory will be
  • One
  • Two
  • Three
  • four
Energy levels A, B, C of a certain atom corresponding to increasing values of energy. i.e., EAB< EC. If λ1, λ2, λ3 are the wavelengths of radiations corresponding to the transitions C to B, B to A and C to A respectively, which of the following statements is correct
Physics-Atoms and Nuclei-63589.png

  • Physics-Atoms and Nuclei-63590.png
  • 2)
    Physics-Atoms and Nuclei-63591.png

  • Physics-Atoms and Nuclei-63592.png

  • Physics-Atoms and Nuclei-63593.png
The angular momentum of electron in nth orbit is given by
  • nh
  • 2)
    Physics-Atoms and Nuclei-63595.png

  • Physics-Atoms and Nuclei-63596.png

  • Physics-Atoms and Nuclei-63597.png
The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between
  • n = 3 to n = 2 states
  • n = 3 to n = 1 states
  • n = 2 to n = 1 states
  • n = 4 to n = 3 states
The ionization energy of 10 times ionized sodium atom is
  • 13.6 eV
  • 13.6 × 11 eV

  • Physics-Atoms and Nuclei-63600.png
  • 13.6 × (11)2 eV
If the wavelength of the first line of the Balmer series of hydrogen is 6561 Å, the wavelength of the second lineof the series should be
  • 13122 Å
  • 3280 Å
  • 4860 Å
  • 2187 Å
The ratio between Bohr radii are
  • 1 : 2 : 3
  • 2 : 4 : 6
  • 1 : 4 : 9
  • 1 : 3 : 5
The spectral series of the hydrogen spectrum that lies in the ultraviolet region is the
  • Balmer series
  • Pfund series
  • Paschen series
  • Lyman series
Suppose an electron is attracted towards the origin by a force k /rwhere \'k\' is a constant and `r\' is the distance ofthe electron from the origin. by applying Bohr model to this system, the radius of the nth orbital of the electron is found to be `rn\' and the kinetic energy of the electron to be ‘Tn’. Then which of the following is true

  • Physics-Atoms and Nuclei-63604.png
  • 2)
    Physics-Atoms and Nuclei-63605.png

  • Physics-Atoms and Nuclei-63606.png

  • Physics-Atoms and Nuclei-63607.png
Which of the following transitions in a hydrogen atom emits photon of the highest frequency
  • n = 1 to n = 2
  • n = 2 to n = 1
  • n = 2 to n = 6
  • n = 6 to n = 2
If the ionization potential of helium atom is 24.6 volt, the energy required to ionise it will be
  • 24.6 eV
  • 24.6 V
  • 13.6 V
  • 13.6 eV
The energy of a hydrogen atom in the ground state is –13.6eV. The energy of a He+ ion in the first excited state will be
  • – 6.8 eV
  • – 13.6 eV
  • – 27.2 eV
  • – 54.4 eV
An electron in the n =1 orbit of hydrogen atom is bounded by 13.6eV. Energy requires to ionize it is
  • 13.6 eV
  • 6.43 eV
  • 5.4 eV
  • 1.51 eV
Ionization energy of hydrogen is 13.6 eV. If h = 6.6 × 10–34J – s, the value of R will be of the order of
  • 1010m–1
  • 107m–1
  • 104m–1
  • 10–7m–1
To explain his theory, Bohr used
  • Conservation of linear momentum
  • Conservation of angular momentum
  • Conservation of quantum frequency
  • Conservation of energy
The ionization energy of hydrogen atom is 13.6 eV. Following Bohr\'s theory, the energy corresponding to a transition between the 3rd and the 4th orbit is
  • 3.40 eV
  • 1.51 eV
  • 0.85 eV
  • 0.66 eV
An alpha nucleus of energy 1/2mv2bombards a heavynuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to
  • 1/m
  • 1 /v4
  • 1 /Ze
  • v2
The radius of hydrogen atom in its ground state is 5.3 × 10–11m. After collision with an electron it is found to have a radius of 21.2 × 10–11m. What is the principal quantum number n of the final state of the atom?
  • n = 4
  • n = 2
  • n =16
  • n = 3
The energy of a hydrogen atom in its ground state is –13.6 eV. The energy of the level corresponding to the quantum number n = 2 (first excited state) in the hydrogen atom is
  • – 2.72 eV
  • – 0.85 eV
  • – 0.54 eV
  • – 3.4 eV
The wavelength of the energy emitted when electron comes from fourth orbit to second orbit in hydrogen is 20.397 cm. The wavelength of energy for the same transition in He+is
  • 81.988 cm–1
  • 5.099 cm–1
  • 20.497 cm–1
  • 40.994 cm–1
Minimum excitation potential of Bohr\'s first orbit in hydrogen atom is
  • 13.6 V
  • 3.4 V
  • 10.2 V
  • 3.6 V
The wavelength of radiation emitted is λ0 when an electron jumps from the third to the second orbit of hydrogen atom. For the electron jump from the fourth to the second orbit of the hydrogen atom, the wavelength of radiation emitted will be

  • Physics-Atoms and Nuclei-63624.png
  • 2)
    Physics-Atoms and Nuclei-63625.png

  • Physics-Atoms and Nuclei-63626.png

  • Physics-Atoms and Nuclei-63627.png
The energy of electron in first excited state of H-atom is– 3.4 eV its kinetic energy is
  • – 3.4 eV
  • + 3.4 eV
  • – 6.8 eV
  • 6.8 eV
If scattering particles are 56 for 90° angle, then at anangle 60° it will be
  • 224
  • 256
  • 98
  • 108
When an electron in hydrogen atom is excited, from its 4th to 5th stationary orbit, the change in angular momentum of electron is (Planck\'s constant:h = 6.6 × 10–34 J-s)
  • 4.16 × 10–34 J-s
  • 3.32 × 10–34 J-s
  • 1.05 × 10–34 J-s
  • 2.08 × 10–34 J-s
The concept of stationary orbits was proposed by
  • Neil Bohr
  • J.J. Thomson
  • Rutherford
  • I. Newton
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