JEE Questions for Physics Atoms And Nuclei Quiz 19 - MCQExams.com


Physics-Atoms and Nuclei-63466.png
  • 109 K
  • 107 K
  • 105 K
  • 103 K
A radioactive isotope X with a half-life of 1.37 × 109 years decays to Y which is stable. A sample of rock from the moon was found to contain both the elements X and Y which were in the ratio of 1 : 7. The age of the rock is
  • 1.96 × 108 years
  • 3.85 × 109 yearsq
  • 4.11 × 109 years
  • 9.59 × 109 years
The half life of radium is 1620 years and its atomic weight is 226 kg per kilomol. The number of atoms that will decay from its 1 g sample per second will be
(Avogadro\'s number N = 6.02 × 1026 atom/kilomol)
  • 3.61 × 1010
  • 3.6 × 1012
  • 3.11 × 1015
  • 31.1 × 1018
The first excited state of hydrogen atom is 10.2 eV above its ground state. The temperature is needed to excite hydrogen atoms to first excited level, is
  • 7.9 × 104 K
  • 3.5 × 104 K
  • 5.8 × 104 K
  • 14 × 104 K
A small quantity of solution containing Na24 radio nuclide of activity 1 microcurie is injected into the blood of a person. A sample of the blood of volume 1 cm3 taken after 5 hours shows an activity of 296 disintegration per minute. What will be the total volume of the blood in the body of the person. Assume that the radioactive solution mixes uniformly in the blood of the person (Take 1 curie = 3.7 × 1010 disintegration per second and e–λr = 0.7927; where λ = disintegration constant)
  • 5.94 litres
  • 2 litres
  • 317 litres
  • 1 litres
A radioactive sample of U238 decays to Pb through a process for which half life is 4.5 × 109 years. The ratio of number of nuclei of Pb to U238 after a time of 1.5 × 109 years (given 21/3 = 1.26)
  • 0.12
  • 0.26
  • 1.2
  • 0.37

Physics-Atoms and Nuclei-63473.png
  • 2
  • 5
  • 4
  • None of these
A radioactive nucleus is being produced at a constant rate α per second. Its decay constant is λ. If N0 are the number of nuclei at time t = 0, then maximum number of nuclei possible are

  • Physics-Atoms and Nuclei-63475.png
  • 2)
    Physics-Atoms and Nuclei-63476.png

  • Physics-Atoms and Nuclei-63477.png

  • Physics-Atoms and Nuclei-63478.png
Binding energy per nucleon plot against the mass number for stable nuclei is shown in the figure. Which curve is correct
Physics-Atoms and Nuclei-63480.png
  • A
  • B
  • C
  • D

Physics-Atoms and Nuclei-63719.png
  • Electron
  • Positron
  • Proton
  • Neutron
A radioactive sample consists of two distinct species having equal number of atoms initially. The mean life time of one species is τ and that of the other is 5τ. The decay products in both cases are stable. A plot is made of the total number of radioactive nuclei as a function of time. Which of the following figures best represents the from of this plot

  • Physics-Atoms and Nuclei-63481.png
  • 2)
    Physics-Atoms and Nuclei-63482.png

  • Physics-Atoms and Nuclei-63483.png

  • Physics-Atoms and Nuclei-63484.png
Radioactive element decays to form a stable nuclide, then rate of decay of reactant (dN/dt) will vary with time (t) as shown in figure

  • Physics-Atoms and Nuclei-63485.png
  • 2)
    Physics-Atoms and Nuclei-63486.png

  • Physics-Atoms and Nuclei-63487.png

  • Physics-Atoms and Nuclei-63488.png
A radioactive sample has N0 active atoms at t = 0. If the rate of disintegration at any time is R and the number of atoms is N, then the ratio R/N varies with time as

  • Physics-Atoms and Nuclei-63490.png
  • 2)
    Physics-Atoms and Nuclei-63491.png

  • Physics-Atoms and Nuclei-63492.png

  • Physics-Atoms and Nuclei-63493.png
The count rate of 10 g of radioactive material was measured at different times and this has been shown in the figure. The half life of material and the total counts (approximately) in the first half life period, respectively are
Physics-Atoms and Nuclei-63495.png
  • 4h, 9000
  • 3h, 14000
  • 3h, 235
  • 3h, 50
The fraction f of radioactive material that has decayed in time t, varies with time t. The correct variation is given by the curve
Physics-Atoms and Nuclei-63497.png
  • A
  • B
  • C
  • D
The plot of the number (N) of decayed atoms versus activity (A) of a radioactive substance is

  • Physics-Atoms and Nuclei-63499.png
  • 2)
    Physics-Atoms and Nuclei-63500.png

  • Physics-Atoms and Nuclei-63501.png

  • Physics-Atoms and Nuclei-63502.png
The graph which represents the correct variation of logarithm of activity (log A) versus time, in figure is
Physics-Atoms and Nuclei-63504.png
  • A
  • B
  • C
  • D
  • Both (and (4)
The charge density in a nucleus varies with distance from the centre of the nucleus according to the curve in fig

  • Physics-Atoms and Nuclei-63506.png
  • 2)
    Physics-Atoms and Nuclei-63507.png

  • Physics-Atoms and Nuclei-63508.png

  • Physics-Atoms and Nuclei-63509.png
A radioactive element A decay into stable element B, initially a fresh sample of A is available. In this sample variation is number of nuclei of B with time is shown by

  • Physics-Atoms and Nuclei-63510.png
  • 2)
    Physics-Atoms and Nuclei-63511.png

  • Physics-Atoms and Nuclei-63512.png

  • Physics-Atoms and Nuclei-63513.png
The curve between the activity A of a radioactive sample and the number of active atoms N is

  • Physics-Atoms and Nuclei-63515.png
  • 2)
    Physics-Atoms and Nuclei-63516.png

  • Physics-Atoms and Nuclei-63517.png

  • Physics-Atoms and Nuclei-63518.png
The graph between number of decayed atoms N’ of a radioactive element and time t is

  • Physics-Atoms and Nuclei-63520.png
  • 2)
    Physics-Atoms and Nuclei-63521.png

  • Physics-Atoms and Nuclei-63522.png

  • Physics-Atoms and Nuclei-63523.png
The de-Broglie wave present in fifth Bohr orbit is

  • Physics-Atoms and Nuclei-63525.png
  • 2)
    Physics-Atoms and Nuclei-63526.png

  • Physics-Atoms and Nuclei-63527.png

  • Physics-Atoms and Nuclei-63528.png
Given below is a plot of binding energy per nucleon Eb, against the nuclear mass M; A, B, C, D E, F correspond to different nuclei. Consider four reactions
(i) A + B → C + ε
(ii) C → A + B + ε
(iii) D + E → F + ε
(iv) F → D + E + ε
where ε is the energy released? In which reactions is
Physics-Atoms and Nuclei-63529.png
  • (i) and (iv)
  • (i) and (iii)
  • (ii) and (iv)
  • (ii) and (iii)

Physics-Atoms and Nuclei-63530.png
  • M2 = 2M1
  • M2 > 2M1
  • M2 < 2M1
  • M1 < 10(mn + mp)
Which of the following statement (s) is/(are) correct?
  • The rest mass of a stable nucleus is less than the sum of the rest masses of its separated nucleons
  • The rest mass of a stable nucleus is greater than the sum of the rest masses of its separated nucleons
  • In nuclear fusion, energy is released by fusing two nuclei of medium mass (approximately 100 amu)
  • In nuclear fission, energy is released by fragmentation of a very heavy nucleus
  • Both (and (4)
In Bohr\'s model of the hydrogen atom
  • The radius of the nth orbit is proportional to n2
  • The total energy of the electron in nth orbit is inversely proportional to n
  • The angular momentum of electron in an nth orbit is an integral multiple of
    Physics-Atoms and Nuclei-63532.png
  • The magnitude of potential energy of the electron in any orbit is greater than its kinetic energy
  • All ((and (4)
From the following equations, pick out the possible nuclear reactions
  • 6C13 + 1H1 → 6C14 + 4.3 MeV
  • 6C12 + 1H1 → 7N13 + 2 MeV
  • 7N14 + 1H1 → 8O15 + 7.3 MeV
  • 92U235 + 0n1 → 54X140 + 38Si94 + 20n1 + γ + 200 MeV
  • Both (and (3)
In a mixture of H – He+ gas (He+ is singly ionized He atom), H atoms and He+ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He+ ions (by collisions). Assume that the Bohr model of atom is exactly valid. The quantum number n of the state finally populated in He+ ions is
  • 2
  • 3
  • 4
  • 5
In a mixture of H – He+ gas (He+ is singly ionized He atom), H atoms and He+ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He+ ions (by collisions). Assume that the Bohr model of atom is exactly valid. The wavelength of light emitted in the visible region by He+ ions after collisions with H atoms is
  • 6.5 × 10–7 m
  • 5.6 × 10–7 m
  • 4.8 × 10–7 m
  • 4.0 × 10–7 m
In a mixture of H – He+ gas (He+ is singly ionized He atom), H atoms and He+ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He+ ions (by collisions). Assume that the Bohr model of atom is exactly valid. The ratio of the kinetic energy of the n = 2 electron for the H atom to that of He+ ion is
  • 1/4
  • 1/2
  • 1
  • 2

Physics-Atoms and Nuclei-63537.png
  • E1 = 2E2
  • E2 = 2E1
  • E1 > E2
  • E2 > E1
The key feature of Bohr\'s theory of spectrum of hydrogen atom is the quantization of angular momentum when an electron is revolving around a proton. We will extend this to a general rotational motion to find quantized rotational energy of a diatomic molecule assuming it to be rigid. The rule to be applied is Bohr\'s quantization condition. A diatomic molecule has moment of inertia I. By Bohr\'s Quantization condition its rotational energy in the nth level (n = 0 is not allowed) is

  • Physics-Atoms and Nuclei-63539.png
  • 2)
    Physics-Atoms and Nuclei-63540.png

  • Physics-Atoms and Nuclei-63541.png

  • Physics-Atoms and Nuclei-63542.png
The key feature of Bohr\'s theory of spectrum of hydrogen atom is the quantization of angular momentum when an electron is revolving around a proton. We will extend this to a general rotational motion to find quantized rotational energy of a diatomic molecule assuming it to be rigid. The rule to be applied is Bohr\'s quantization condition.
Physics-Atoms and Nuclei-63544.png
  • 2.76 × 10–46 kg m2
  • 1.87 × 10–46 kg m2
  • 4.67 × 10–47 kg m2
  • 1.17 × 10–47 kg m2
The key feature of Bohr\'s theory of spectrum of hydrogen atom is the quantization of angular momentum when an electron is revolving around a proton. We will extend this to a general rotational motion to find quantized rotational energy of a diatomic molecule assuming it to be rigid. The rule to be applied is Bohr\'s quantization condition. In a CO molecule, the distance between C (mass =12 amu) and O (mass =16 amu), where
Physics-Atoms and Nuclei-63546.png
  • 2.4 × 10–10 m
  • 1.9 × 10–10 m
  • 1.3 × 10–10 m
  • 4.4 × 10–11 m

Physics-Atoms and Nuclei-63548.png
  • Zero
  • Much less than 0.8 × 10–6 eV
  • Nearly 0.8 × 106 eV
  • Much larger that 0.8 × 106 eV

Physics-Atoms and Nuclei-63550.png
  • 0 ≤ K ≤ 0.8 × 106 eV
  • 3.0eV ≤ K ≤ 0.8 × 106 eV
  • 3.0eV ≤ K < 0.8 × 106 eV
  • 0 ≤ K < 0.8 × 106 eV
Which of the following is the fusion reaction?
  • 1H2 + 1H2 → 2He4
  • 0n1 + 7N14 → 6C14 + 1H1
  • 0n1 + 92U238 → 93Np239 + β–1 + γ
  • 1H3 → 2He3 + β–1 + γ
The activity of a freshly prepared radioactive sample is 1010 disintegrations per second, whose mean life is 109 s. The mass of an atom of this radioisotope is 10–25 kg. The mass (in mg) of the radioactive sample is
  • 1
  • 3
  • 4
  • 6
Four physical quantities are listed in Column I. Their values are listed in Column II in a random order
Physics-Atoms and Nuclei-63553.png
  • A → p, B → r, C → r, D → q
  • A → p, B → r, C → q, D → r
  • A → p, B → r, C → q, D → p
  • A → p, B → r, C → q, D → s

Physics-Atoms and Nuclei-63554.png

  • Physics-Atoms and Nuclei-63555.png
  • 2)
    Physics-Atoms and Nuclei-63556.png

  • Physics-Atoms and Nuclei-63557.png

  • Physics-Atoms and Nuclei-63558.png
Which sample contains greater number of nuclei: a 5.00 – μCi sample of 240Pu (half-life 6560y) or a 4.45 – µCi sample of 243Am (half-life 7370y)?
  • 240Pu
  • 243Am
  • Equal in both
  • 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 × 1019 J
  • 3.4 × 1.6 × 1019 J
  • 1.51 × 1.6 × 1019 J
  • 0
When a sample of solid lithium is placed in a flask of hydrogen gas then following reaction happened
Physics-Atoms and Nuclei-63562.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 = Avogrado No)

  • Physics-Atoms and Nuclei-63563.png
  • 2)
    Physics-Atoms and Nuclei-63564.png

  • Physics-Atoms and Nuclei-63565.png

  • Physics-Atoms and Nuclei-63566.png
Highly energetic electrons are bombarded on a target of an element containing 30 neutrons. The ratio of radii of nucleus to that of Helium nucleus is 141/3. The atomic number of nucleus will be
  • 25
  • 26
  • 56
  • 30
The fission of 235U can be triggered by the absorption of slow neutrons by a nucleus. Similarly a slow proton can also be used. This statements is
  • Correct
  • Wrong
  • Information is insufficient
  • None of these
Assertion 90Sr from the radioactive falling out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment. of the production of red blood cells. Reason The energetic β-particles emitted in the decay of 90Sr damage the bone marrow.
  • 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 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.
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