JEE Questions for Physics Atoms And Nuclei Quiz 6 - MCQExams.com

The counting rate observed from a radioactive source at t = 0 was 1600 counts-1 and at t = 8s it 100 counts-1. the counting rate observed as counts per second at t = 6s, will be
  • 400
  • 300
  • 250
  • 200
A freshly prepared radioactive source of half-life 2 h emits radiation of intensity which is 64 times the permissible safe level. Calculate the minimum time after which it would be possible to work safely with this source.
  • 12 h
  • 24 h
  • 6 h
  • 130 h
Half-life of a radioactive substance A is 4 days. the probability that a nucleus will decay in two half - life is
  • 1/4
  • 3/4
  • 1/2
  • 1
The energy spectrum of β- particles (number N(E)) as a function of β - energy E) emitted a radioactive source is

  • Physics-Atoms and Nuclei-62613.png
  • 2)
    Physics-Atoms and Nuclei-62614.png

  • Physics-Atoms and Nuclei-62615.png

  • Physics-Atoms and Nuclei-62616.png
In artificial radioactivity, 1.414 × 106 nuclei are disintegration into 106 nuclei in 10 min. The half-life in minutes must be
  • 5
  • 20
  • 15
  • 30
The half-life of radon is 3.8 days. How many radon will be left out of 1024 mg after 38 days
  • 1 mg
  • 2 mg
  • 3 mg
  • 4 mg
  • 7 mg
A radioactive nucleus A finally transforms into a stable nucleus B. Then. A and B can be
  • isobars
  • isotones
  • isotopes
  • None of these
A radioactive substance has a half-iife of four months. Three-fourth of the substance will decay in
  • 3 month
  • 4 month
  • 8 month
  • 12 month
Starting with a sample of pure 66Cu, 7/8 of it decays into Zn in 15 min. The corresponding half - life is
  • 10 min
  • 15 min
  • 5 min

  • Physics-Atoms and Nuclei-62618.png
Mean life of a radioactive sample is 100 s. Then. its half-life (in minutes) is
  • 1
  • 0.693
  • 10-4
  • 1.155
Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion 5 billion years ago. The probability of decay during the next time is
  • different for each nuclei
  • nuclei created in explosion decays first
  • nuclei created in the reactor decays first
  • independent of the time of creation

Physics-Atoms and Nuclei-62619.png
  • 69, 171
  • 70, 172
  • 68, 172
  • 69, 172
If half-life of radium is 77 days, its decay constant will be
  • 3 × 10-3 day-1
  • 9 × 10-3 day-1
  • 1 × 10-3 day-1
  • 6 × 10-3 day-1
In a radioactive reaction
92 X232 → 82 X204
the number of α - particles emitted is
  • 7
  • 6
  • 5
  • 4
If in a nuclear fission, piece of uranium of mass 5.0 g is lost, the energy obtained in kWh is
  • 1.25 × 107
  • 2.25 × 107
  • 3.25 × 107
  • 0.25 × 107
Which of the following fusion reactions will not result in the net release of energy
I. 6Li + 6Li
II. 4He + 4He
III. 12C + 12C
IV. 35CI + 35CI
  • I
  • II
  • III
  • IV
A radioactive substance has an average life of 5 h. In a time of 5 h
  • half of the active nuclei decay
  • less than half of the active nuclei decay
  • more than half of the active nuclei decay
  • all active nuclei decay

Physics-Atoms and Nuclei-62621.png
  • less than 1
  • greater 1
  • equal 1
  • depends on the mass of parent nucleus
X + 14N7 → 17O8 + 1P1. What is the X?
  • Helium
  • Deutron
  • Neutrino
  • Positron
A nucleus of mass M + ∆m is at rest and decays into two daughter nuclei of equal mass (M/each. Speed of light is c.
The speed of daughter nuclei is

  • Physics-Atoms and Nuclei-62623.png
  • 2)
    Physics-Atoms and Nuclei-62624.png

  • Physics-Atoms and Nuclei-62625.png

  • Physics-Atoms and Nuclei-62626.png
Assume the graph of specific binding energy versus mass number- is as shown in the figure. Using this graph, select the correct choice from the following.
Physics-Atoms and Nuclei-62628.png
  • Fusion of two nuclei of mass number lying in the range of 100 < .4 < 200 will release energy
  • Fusion of two nuclei of mass number lying in the range of 51 < A < 100 will release energy
  • Fusion of two nuclei of mass number lying in the range of 1 < A < 50 will release energy
  • Fission of the nucleus of mass number lying in the rang of 100 < A < 200 will release energy when broken into two fragments
Pick out the correct statement from the following.
  • Energy released per unit mass of the reactant is less in case of fusion reaction
  • Packing fraction may be positive or may he negative
  • Pu239 is not suitable for a fission reaction
  • For stable nucleus, the specific binding energy is low
The energy released in the explosion of an atom bomb is mainly due to
  • nuclear fusion
  • nuclear fission
  • controlled nuclear chain reaction
  • None of the above

Physics-Atoms and Nuclei-62629.png
  • Both A and R are correct and R is the explanation of A
  • Both A and R are correct and R is not a explanation of A
  • A is correct but R is incorrect
  • A is incorrect but R is correct
The phenomena in which proton flips is
  • nuclear magnetic resonance
  • lasers
  • radioactivity
  • nuclear fusion
FPe represents electrical force on proton due to electron and FPe on electron due to proton in a hydrogen atom. Similarly, FPe represents the gravitational force on proton due to electron and FPe the corresponding force on electron due to proton. Which of the following is not true?
  • FPe + FPe = 0
  • F'Pe + F'Pe = 0
  • FPe + F'Pe + FPe +F'Pe = 0
  • FPe + F'Pe = 0
Using the following data :
Mass of hydrogen atom = 1.00783 u
Mass of neutron = 1.00867 u
Mass of nitrogen atom(7N14) = 14.00307 u
The calculated value of the binding energy of the nucleus of the nitrogen atom (7N14) is close to
  • 56 MeV
  • 98 MeV
  • 104 MeV
  • 112 MeV
This question contains Statement I and Statement II of the fbur choices given after the statements, choose the one of that best describes the two statements.
Statement I Energy is released when heavy nuclei undergo fission of 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.
  • If both Statement 1 and Statement II are incorrect and statement II is the correct explanation of the statement 1
  • If both Statement i and Statement II are correct but Statement 11 is not the correct explanation of statement I
  • If Statemetn I is correct, but the Statement II is false
  • If Statement I is incorrect, hut the Statement 11 is correct
The nuclear fusion reaction is given
1H2 + 1H2 → 0He3 + 0n1 + Q (energy).
If 2 mole of deuterium fused the total released energy is
  • 2Q
  • 4Q
  • Q × 6.02 × 1023
  • Q × 2 × 6 × 1023
Which one of the following is correct about fission?
  • Approx 0.1% mass converts into energy
  • Most of energy of fission is in the form of heat
  • In a fission of U235, about 200 MeV energy is released
  • On an average, one neutron is released per fission of U235
On bombarding U235 by slow neutron, 200 MeV energy is released. If the power output of atomic reactor is 1.6 MW, then the rate of fission will be
  • 5 × 1022 s-1
  • 5 × 1016 s-1
  • 8 × 1016 s-1
  • 20 × 1016 s-1
The energy released in the fission of 1 kg of 92U235 is (energy per fission = 200 MeV)
  • 5.1 × 1026 eV
  • 5.1 × 1026 J
  • 8.2 × 1033 J
  • 8.2 × 1013 MeV
  • 5.1 × 1023 MeV
Cadmium rods are used in a nuclear reactor for
  • slowing down fast neutrons
  • speeding up slow neutrons
  • absorbing neutrons
  • regulating the power level of reactor
For a nuclear to be in critical condition, the value of neutron multiplication factor (k) must be
  • k > 1
  • k < 1
  • k = 1
  • k = 0
What is the Q-value of the reaction
p + 7Li →4He + 4He.
The atomic masses of 1H, 4He and 7Li are 1.007825 u, 4.002603 u and 7.016004 u, respectively
  • 17.35 MeV
  • 18.06 MeV
  • 177.35 MeV
  • 170.35 meV
Consider the nuclear reaction X200 →A110 + B80. If the binding energy per nucleon for X, A and B are 7.4 MeV, 8.2 MeV and 8.1 MeV respectively, then the energy released in the reaction is
  • 70 MeV
  • 200 MeV
  • 190 MeV
  • 10 MeV
  • 1480 MeV
If in a nuclear fusion process, the masses of the fusing nuclei be m1 and m2 and the mass of the resultant nucleus be m3, then
  • m3 = m1 + m2
  • m3 = |m1 – m2|
  • m3 < (m1 + m2)
  • m3 > (m1 + m2)
Nuclear fission can be explained based on
  • Millikan's oil drop method
  • Liquid drop model
  • Shell model
  • Bohr's model
If 200 MeV energy is released in the fission of a single nucleus of 92U235. How many fissions must occur per second to produce a power of 1 KW ?
  • 3.125 × 1013
  • 6.250 × 1013
  • 1.525 × 1013
  • None of these
Hydrogen bomb is based upon
  • fission
  • fusion
  • chemical reaction
  • transmutation
Which of the following is a fusion reaction?
  • 1H2 + 1H2 → 2He4
  • 1H2 + 1H2 → 2(1H2)
  • 1H1 + 1H1 → 2He4
  • 1H1 + 1H2 → 2He4 + n
The fussion process is possible at high temperatures, because at higher temperatures
  • the nucleus disintegrates
  • the molecules disintegrates
  • atoms become ionised
  • the nucleus get sufficient energy to overcome the strong forces of repulsion
For maintaining sustained chain reaction, the following is
  • protons
  • electrons
  • neutrons
  • positions
Atomic reactor is based on
  • controlled chain reaction
  • uncontrolled chain reaction
  • nuclear fission
  • nuclear fussion
Solid CO2 forms
  • Ionic bonds
  • Vander Waal bonds
  • Chemical bonds
  • Covalent bonds
What is the radius of Iodine atom? (At. no. 53, mass no. 126)
  • 2.5 × 10–11 m
  • 2.5 × 10–9 m
  • 7 × 10–9 m
  • 7 × 10–6 m
Hydrogen atom emits blue light when it changes from n = 4 energy level to the n = 2 level. Which color of light would from the n = 5 level to the n = 2 level.
  • Red
  • Yellow
  • Green
  • Violet
In H spectrum, the wavelength of Hα line is 656 nm whereas in a distant galaxy, the wavelength of Hα line is 706 nm. Estimate the speed of galaxy with respect to earth.
  • 2 × 108 m/s
  • 2 × 107 m/s
  • 2 × 106 m/s
  • 2 × 105 m/s
If the electron in a hydrogen atom jumps from an orbit with level n1 = 3 to an orbit with level n1 = 2, the emitted radiation has a wavelength given by

  • Physics-Atoms and Nuclei-62638.png
  • 2)
    Physics-Atoms and Nuclei-62639.png

  • Physics-Atoms and Nuclei-62640.png

  • Physics-Atoms and Nuclei-62641.png
If the wavelength of the first line of the Balmer series of hydrogen is 6561Å, the wavelength of the second line of the series should be
  • 13122 Å
  • 3280 Å
  • 4860 Å
  • 2187 Å
0:0:1


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