JEE Questions for Physics Atoms And Nuclei Quiz 14 - MCQExams.com

Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is
  • 54.4 eV
  • 13.6 eV
  • 40.8 eV
  • 27.2 eV
The rate of disintegration was observed to be 1017 disintegrations per sec when its half life period is 1445 years. The original number of particles are
  • 8.9 × 1027
  • 6.6 × 1027
  • 1.4 × 1016
  • 1.2 × 1017
An atomic power nuclear reactor can deliver 300 MW. The energy released due to fission of each nucleus of uranium atom U238 is 170 MeV. The number of uranium atoms fissioned per hour will be
  • 30 × 1025
  • 4 × 1022
  • 10 × 1020
  • 5 × 1015
A hydrogen like atom of atomic number Z is in an excited state of quantum number 2n. It can emit a maximum energy photon of 204 eV. If it makes a transition to quantum state n, a photon of energy 40.8 eV is emitted. The value of n will be
  • 1
  • 2
  • 3
  • 4
A radioactive sample is α–emitter with half life 138.6 days is observed by a student to have 2000 disintegration/s. The number of radioactive nuclei for given activity are
  • 3.45 × 1010
  • 1 × 1010
  • 3.45 × 1015
  • 2.75 × 1011
Rest mass energy of an electron is 0.54 MeV. If velocity of the electron is 0.8 c, then K.E. of the electron is
  • 0.36 MeV
  • 0.41 MeV
  • 0.48 MeV
  • 1.32 MeV
If one starts with one curie of radioactive substance (T1/2 = 12 hrs) the activity left after a period of 1 week will be about
  • 1 curie
  • 120 micro curie
  • 60 micro curie
  • 8 mili curie
The distance of closest approach of an α–particle fired towards a nucleus with momentum p, is r. If the momentum of the α–particle is 2p, the corresponding distance of closest approach is
  • r/2
  • 2r
  • 4r
  • r /8
  • r/4
Binding energy per nucleon verses mass number curve for nuclei is shown in the figure. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is
Physics-Atoms and Nuclei-63044.png
  • Y → 2Z
  • W → X + Z
  • W → 2Y
  • X → Y + Z
If in hydrogen atom, radius of nth Bohr orbit is rn, frequency of revolution of electron in nth orbit is fn, choose the correct option

  • Physics-Atoms and Nuclei-63046.png
  • 2)
    Physics-Atoms and Nuclei-63047.png

  • Physics-Atoms and Nuclei-63048.png
  • Both (a) and (b)
The graph between the instantaneous concentration (N) of a radioactive element and time (t) is

  • Physics-Atoms and Nuclei-63050.png
  • 2)
    Physics-Atoms and Nuclei-63051.png

  • Physics-Atoms and Nuclei-63052.png

  • Physics-Atoms and Nuclei-63053.png
In Fig. X represents time and Y represents activity of a radioactive sample. Then the activity of sample, varies with time according to the curve
Physics-Atoms and Nuclei-63055.png
  • A
  • B
  • C
  • D

Physics-Atoms and Nuclei-63057.png
  • 4
  • 3
  • 2
  • 1
The radioactivity of a given sample of whisky due to tritium (half life 12.3 years) was found to be only 3% of that measured in a recently purchased bottle marked \ 7 years old\ . The sample must have been prepared about
  • 220 years back
  • 300 years back
  • 400 years back
  • 70 years back
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-63059.png
  • 0.265 Å
  • 0.53 Å
  • 0.132 Å
  • None of these
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 600 Bq. activity at noon on January 24 will be
  • 75 Bq
  • Less than 75 Bq
  • More than 75Bq
  • 150 Bq
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, the activity of the sample and the disintegration constant of the sample are respectively
  • Increases, remains the same
  • Decreases, increases
  • Decreases, remains same
  • Increases, decreases
At a given instant there are 25% undecayed radioactive nuclei. After 10 s the number of undecayed nuclei reduces to 6.25%, the mean life of the nuclei is
  • 14.43 s
  • 7.21 s
  • 5 s
  • 10 s
The ratio of ionization energy of Bohr\'s hydrogen atom and Bohr\'s hydrogen like lithium atom is
  • 1 : 1
  • 1 : 3
  • 1 : 9
  • None of these
Consider a hypothetical annihilation of a stationary electron with a stationary positron. What is the wavelength of resulting radiation
(h = Planck\'s constant, c = speed of light, m0 = rest mass)

  • Physics-Atoms and Nuclei-63066.png
  • 2)
    Physics-Atoms and Nuclei-63067.png

  • Physics-Atoms and Nuclei-63068.png

  • Physics-Atoms and Nuclei-63069.png
In a sample of hydrogen like atoms all of which are in ground state, a photon beam containing photons of various energies is passed. In absorption spectrum, five dark lines, are observed. The number of bright lines in the emission spectrum will be (assume that all transitions takes place)
  • 5
  • 10
  • 15
  • None of these
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 × 10–2 ms–1
  • 4ms–1
  • 8 × 102ms–1
Number of nuclei of a radioactive substance at time t = 0 are 1000 and 900 at time t = 2 s. Then number of nuclei at time t = 4 s will be
  • 800
  • 810
  • 790
  • 700
The ratio between total acceleration of the electron in singly ionized helium atom and hydrogen atom (both in ground state) is
  • 1
  • 8
  • 4
  • 16
If the series limit of Lymen series for Hydrogen atom is equal to the series limit of Balmer series for a hydrogen like atom, then atomic number of this hydrogen like atom will be
  • 1
  • 2
  • 3
  • 4
Two protons are kept at a separation of 40Å. Fn is the nuclear force and Fe is the electrostatic force between them. Then,
  • Fn >> Fe
  • Fn = Fe
  • Fn << Fe
  • Fn ≈ Fe
When a hydrogen atom is bombarded, the atom is exicted to the n = 4 state. The energy released, when the atom goes from n = 4 state to the ground state is
  • 1.275 eV
  • 12.75 eV
  • 5 eV
  • 8 eV
The Fig. indicates the energy levels of a certain atom. When the system moves from 2 E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from 4E/3 level to E is
Physics-Atoms and Nuclei-63077.png

  • Physics-Atoms and Nuclei-63078.png
  • 2)
    Physics-Atoms and Nuclei-63079.png

  • Physics-Atoms and Nuclei-63080.png

  • Physics-Atoms and Nuclei-63081.png
The nucleus at rest disintegrate into two nuclear parts which have their velocities in the ratio 2 : 1 The ratio of their nuclar sizes will be

  • Physics-Atoms and Nuclei-63082.png
  • 2)
    Physics-Atoms and Nuclei-63083.png

  • Physics-Atoms and Nuclei-63084.png

  • Physics-Atoms and Nuclei-63085.png
In each of the following question match column -I and `column -II select correct
Physics-Atoms and Nuclei-63087.png
  • a → s, b → r, c → q, d → p
  • a → r, b → p, c → q, d → s
  • a → p, b → r, c → s, d → q
  • b → p, c → q, b → r, d → s
Assertion :- In a radio-active disintegration, an election is emitted by nucleus.
Reason :- eleccon are always Present in-side the nucleus.
  • Both assertion and reason are true. Reason is the correct explanation of the Assertion
  • Both assertion and reason are true. Reason is not correct explanation of the assertion
  • Assertion is true but reason is false.
  • Both Assertion and Reason are false
Assertion :- An election and Positon can annibilate each other creating Photon.
Reason :- Electon and Positon form a Particle and anti Particle.
  • Both assertion and reason are true. Reason is the correct explanation of the Assertion
  • Both assertion and reason are true. Reason is not correct explanation of the assertion
  • Assertion is true but reason is false.
  • Both Assertion and Reason are false
Assetion :- An isolated radioactive atom may not decay at all what ever be its half time
Reason :- Radioactive decay is a statistical Phenomena.
  • Both Assertion and reason are true. Reason is the correct explanation of the Assertion
  • Both Assertion and reason are true. Reason is not correct explanation of the Assertion
  • Assertion is true but reason is false.
  • Both Assertion and Reason are false
Assertion :- Fragment Produced in the fission of u235 are active Reason :- The fragments have abnormally high Proton to neutron ratio
  • Both assertion and reason are true. Reason is the correct explanation of the Assertion
  • Both assertion and reason are true. Reason is not correct explanation of the assertion
  • Assertion is true but reason is false
  • Both Assertion and Reason are false
statement-I :- Large angle scattering of al-pha Particle led to discovery of atomic nucleus.
state ment-II :- Entire Positive charge of atom is concentrated in the central core.
  • statement -I and II are true. and statement II is correct explanation of statement-I
  • statement -I and II are true, but statement-II is not correct explanation of statement I
  • statement I is true, but state ment II is false.
  • statement I is false but statement II is true
Statement-I : 1 amu = 931.48 MeV
Statement-II : It follows form E = mc2
  • statement -I and II are true. and statement II is correct explanation of statement-I
  • statement -I and II are true, but statement-II is not correct explanation of statement I
  • statement I is true, but state ment II is false.
  • statement I is false but statement II is true
Orbital acceleration of electron is

  • Physics-Atoms and Nuclei-63326.png
  • 2)
    Physics-Atoms and Nuclei-63327.png

  • Physics-Atoms and Nuclei-63328.png

  • Physics-Atoms and Nuclei-63329.png
Statement -I :-half life time of tritium is 12.5 years
Statement-II :- The fraction of tritium that remains after 50 years is 6.25%
  • statement -I and II are true. and statement II is correct explanation of statement-I
  • statement -I and II are true, but statement-II is not correct explanation of statement I
  • statement I is true, but state ment II is false.
  • statement I is false but statement II is true
Statement-I :- Nuclei of different atoms have same size
Statement-II :- R=Ro(A)1/3
  • statement -I and II are true. and statement II is correct explanation of statement-I
  • statement -I and II are true, but statement-II is not correct explanation of statement I
  • statement I is true, but state ment II is false
  • statement I is false but statement II is true
Match column I and II and chose correct Answer form the given below.
Physics-Atoms and Nuclei-63088.png
  • a → p, b → r, c → d, d → q
  • a → d, b → r, c → p, d → a
  • a → q, b → r, c → d, d → p
  • a → r, b → a, c → p, d → a
A radioative sample has no active atom at t = o, at the rate of dissntegration at any time is R and the number of atom is N, then ratio. (R/N) varies with time (t) as.

  • Physics-Atoms and Nuclei-63089.png
  • 2)
    Physics-Atoms and Nuclei-63090.png

  • Physics-Atoms and Nuclei-63091.png

  • Physics-Atoms and Nuclei-63092.png
The transition the state n = 4 to n = 1 in a hydrogen like atom results in ultraviolet radiation. Infrared radition will be obtained in the transition form
  • 3 → 2
  • 5 → 4
  • 4 → 2
  • 2 → 1
In Bohr model the hydogen atom, the lowest orbil corresponds to
  • Intinite energy
  • zero energy
  • The minimum energy
  • The maximum energy
Energy levels A , B , C of a certain atom corresponding values of energy i.e. EA < EB < EC. If λ1, λ2, λ3 are wave lengths of radition corresponding to the transition C → B, B → A and C → A. Which of the following is correct

  • Physics-Atoms and Nuclei-63095.png
  • 2)
    Physics-Atoms and Nuclei-63096.png

  • Physics-Atoms and Nuclei-63097.png

  • Physics-Atoms and Nuclei-63098.png
According to Bohr\'s theory the radius of electron in an orbit described by Principal quantum number n and atomic number Z, is Proportional to.

  • Physics-Atoms and Nuclei-63100.png
  • 2)
    Physics-Atoms and Nuclei-63101.png

  • Physics-Atoms and Nuclei-63102.png

  • Physics-Atoms and Nuclei-63103.png
The energy of electron in the nth orbit of hydogen atom is expressed as
Physics-Atoms and Nuclei-63105.png
  • 910 Å, 1213 Å
  • 1315 Å ,1530 Å
  • 5463 Å ,7858 Å
  • None of these

Physics-Atoms and Nuclei-63107.png

  • Physics-Atoms and Nuclei-63108.png
  • 2)
    Physics-Atoms and Nuclei-63109.png

  • Physics-Atoms and Nuclei-63110.png

  • Physics-Atoms and Nuclei-63111.png

Physics-Atoms and Nuclei-63113.png
  • Be9
  • F19
  • C12
  • Li7

Physics-Atoms and Nuclei-63115.png

  • Physics-Atoms and Nuclei-63116.png
  • 2)
    Physics-Atoms and Nuclei-63117.png

  • Physics-Atoms and Nuclei-63118.png

  • Physics-Atoms and Nuclei-63119.png
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