JEE Questions for Physics Atoms And Nuclei Quiz 21 - MCQExams.com

In a hydrogen atom, the distance between the electron and proton is 2.5 × 10–11 m. The electrical force ofattraction between them will be
  • 2.8 × 10–7 N
  • 3.7 × 10–7 N
  • 6.2 × 10–7 N
  • 9.1 × 10–7 N
If λmax is 6563 Å, then wavelength of second line for Balmer series will be

  • Physics-Atoms and Nuclei-63634.png
  • 2)
    Physics-Atoms and Nuclei-63635.png

  • Physics-Atoms and Nuclei-63636.png
  • None of these
What will be the angular momentum of an electron, if energy of this electron in H–atom is –1.5 eV (in J-s)?
  • 1.05 × 10–34
  • 2.1 × 10–34
  • 3.15 × 10–34
  • –2.1 × 10–34
Who discovered spin quantum number?
  • Uhlenbeck & Goudsmit
  • Niels's Bohr
  • Zeeman
  • Sommerfeld
In Bohr\'s model, if the atomic radius of the first orbit is r0, then the radius of the fourth orbit is
  • r0
  • 4r0
  • r0 / 16
  • 16r0
In hydrogen atom, it the difference in the energy of the electron in n = 2 and n = 3 orbits is E, the ionization energy of hydrogen atom is
  • 13.2 E
  • 7.2E
  • 5.6E
  • 3.2 E
The first member of the Paschen series in hydrogen spectrum is of wavelength 18,800 Å. The shortwavelength limit of Paschen series is
  • 1215 Å
  • 6560 Å
  • 8225 Å
  • 12850 Å
The ratio of the longest to shortest wavelengths in Lyman series of hydrogen spectra is

  • Physics-Atoms and Nuclei-63642.png
  • 2)
    Physics-Atoms and Nuclei-63643.png

  • Physics-Atoms and Nuclei-63644.png

  • Physics-Atoms and Nuclei-63645.png
The radius of the Bohr orbit in the ground state of hydrogen atom is 0.5 Å. The radius of the orbit of the electron in the third excited state of He+ will be
  • 8 Å
  • 4 Å
  • 0.5 Å
  • 0.25 Å
The ratio of the speed of the electron in the first Bohr orbit of hydrogen and the speed of light is equal to (where e, h and c have their usual meanings)
  • 2πhc /e2
  • e2h /2πc
  • e2c /2πh
  • 2πe2/hc
According to the Rutherford\'s atomic model, the electrons inside the atom are
  • Stationary
  • Not stationary
  • Centralized
  • None of these
Rutherford\'s α–particle experiment showed that the atoms have
  • Proton
  • Nucleus
  • Neutron
  • Electrons
The diagram shows the path of four α–particles of the same energy being scattered by the nucleus of an atom simultaneously. Which of these are/is not physically possible?
Physics-Atoms and Nuclei-63649.png
  • 3 and 4
  • 2 and 3
  • 1 and 4
  • 4 only
An electron jumps from 5th orbit to 4th orbit of hydrogen atom. Taking the Rydberg constant as 107 per metre what will be the frequency of radiation emitted
  • 6.75 × 1012 Hz
  • 6.75 × 1014 Hz
  • 6.75 × 1013 Hz
  • None of these
For principal quantum number n = 3, the possible values of orbital quantum number \'1\' are
  • 1, 2, 3
  • 0, 1, 2, 3
  • 0, 1, 2,
  • –1, 0, +1
Four lowest energy levels of H–atom are shown in the figure. The number of possible emission lines would be
Physics-Atoms and Nuclei-63653.png
  • 3
  • 4
  • 5
  • 6
The order of the size of nucleus and Bohr radius of an atom respectively are
  • 1014 m, 10–10 m
  • 10–10 m, 10–8 m
  • 10–20 m, 10–16 m
  • 10–8 m, 10–6 m
Minimum energy required to takeout the only oneelectron from ground state of He+is
  • 13.6 eV
  • 54.4 eV
  • 27.2 eV
  • 6.8 eV
In which of the following decay, the element does not change?
  • β–decay
  • α–decay
  • γ–decay
  • None of these
The frequency of 1st line of Balmer series in H2 atom is v0. The frequency of line emitted by singly ionized Heatom is
  • 2v0
  • 4v0
  • v0 /2
  • v0 /4

Physics-Atoms and Nuclei-63658.png
  • 5.1 V
  • 12.1 V
  • 17.2 V
  • 7 V
The possible quantum numbers for 3d electrons are

  • Physics-Atoms and Nuclei-63660.png
  • 2)
    Physics-Atoms and Nuclei-63661.png

  • Physics-Atoms and Nuclei-63662.png

  • Physics-Atoms and Nuclei-63663.png
The radius of the first (lowest) orbit of the hydrogen atom is a0. The radius of the second (next higher) orbit will be
  • 4a0
  • 6a0
  • 8a0
  • 10a0
In which of the following systems will the radius of the first orbit (n =be minimum?
  • Single ionized helium
  • Deuterium atom
  • Hydrogen atom
  • Doubly ionized lithium
The shortest wavelength in the Lyman series of hydrogen spectrum is 912 Å corresponding to a photon energy of 13.6 eV. The shortest wavelength in theBalmer series is about
  • 3648 Å
  • 8208 Å
  • 1228 Å
  • 6566 Å

Physics-Atoms and Nuclei-63667.png
  • 1.5 eV
  • 0.85 eV
  • 3.4 eV
  • 1.9 eV
The Bohr model of atom
  • Assumes that the angular momentum of electrons is quantized
  • Uses Einstein's photo-electric equation
  • Predicts continuous emission spectra for atoms
  • Predicts the same emission spectra for all types of atoms
Taking Rydberg\'s constant RH = 1.097 × 107 m, firstand second wavelength of Balmer series in hydrogen spectrum is
  • 2000 Å, 3000 Å
  • 1575 Å,2960 Å
  • 6529 Å, 4280 Å
  • 6552 Å, 4863 Å
Which of the relation is correct between time period and number of orbits while an electron is revolving in an orbit?

  • Physics-Atoms and Nuclei-63671.png
  • 2)
    Physics-Atoms and Nuclei-63672.png

  • Physics-Atoms and Nuclei-63673.png

  • Physics-Atoms and Nuclei-63674.png
The ground state energy of hydrogen atom is –13.6 eV. What is the potential energy of the electron in this state?
  • 0 eV
  • –27.2 eV
  • 1 eV
  • 2 eV
The magnetic moment (µ) of a revolving electron around the nucleus varies with principal quantum number n as

  • Physics-Atoms and Nuclei-63677.png
  • 2)
    Physics-Atoms and Nuclei-63678.png

  • Physics-Atoms and Nuclei-63679.png

  • Physics-Atoms and Nuclei-63680.png
An electron with kinetic energy 5 eV is incident on a H–atom in its ground state. The collision
  • Must be elastic
  • May be partially elastic
  • Must be completely elastic
  • May be completely inelastic
The radius of an electron orbit in a hydrogen atom is of the order of
  • 10–8 m
  • 10–9 m
  • 10–11 m
  • 10–13 m
If electron in a hydrogen atom has moved from n = 1 to n = 10 orbit, the potential energy of the system has
  • Increased
  • Decreased
  • Remained unchanged
  • Become zero
The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is
  • 2
  • 3
  • 4
  • 1
Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr\'s atomic model
  • 13.6 eV
  • 0.65 eV
  • 1.9 eV
  • 11.1 eV
Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths λ1 :λ2emitted in the two cases is
  • 7/5
  • 27/20
  • 27/5
  • 20/7
Which of the following particles are constituents of the nucleus
  • Protons and electrons
  • Protons and neutrons
  • Neutrons and electrons
  • Neutrons and positrons

Physics-Atoms and Nuclei-63687.png
  • 23 MeV
  • 46 MeV
  • 5.6 MeV
  • 3.9 MeV
Size of nucleus is of the order of
  • 10–10 m
  • 10–15 m
  • 10–12 m
  • 10–19 m
For effective nuclear forces, the distance should be
  • 10–10 m
  • 10–13 m
  • 10–15 m
  • 10–20 m
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)
  • 28.4 MeV
  • 20.8 MeV
  • 27.3 MeV
  • 14.2 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?
  • 28
  • 7
  • 4
  • 1

Physics-Atoms and Nuclei-63694.png
  • 1 MeV
  • 11.9 MeV
  • 23.8 MeV
  • 931 MeV
The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an
  • Isobar of parent
  • Isomer of parent
  • Isotone of parent
  • Isotope of parent
The average binding energy per nucleon is maximum for the nucleus
  • 2He4
  • 8O16
  • 26Fe56
  • 92U238
Which of the following pairs is an isobar?
  • 1H1 and 1H2
  • 1H2 and 1H3
  • 6C12 and 6C13
  • 15P30 and 14Si30
Equivalent energy of mass equal to 1 a.m.u. is
  • 931 KeV
  • 931 eV
  • 931 MeV
  • 9.31 MeV

Physics-Atoms and Nuclei-63697.png

  • Physics-Atoms and Nuclei-63698.png
  • 2)
    Physics-Atoms and Nuclei-63699.png

  • Physics-Atoms and Nuclei-63700.png

  • Physics-Atoms and Nuclei-63701.png
Outside a nucleus
  • Neutron is stable
  • Proton and neutron both are stable
  • Neutron is unstable
  • Neither neutron nor proton is stable
0:0:1


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