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CBSE Questions for Class 12 Medical Physics Nuclei Quiz 1 - MCQExams.com

For a nucleus to be stable, the correct relation between neutron number N and proton number Z is 

  • N>Z
  • N=z
  • N<Z
  • NZ
Let u denote one atomic mass unit. One atom of an element of mass number A has mass exactly equal to Au
  • for any value of A
  • only for A=1
  • only for A=12
  • for any value of A provided the atom is stable
In the nuclear reaction ; 92U238zThA+2He4 the values of A and Z are: 
  • A=230,Z=8
  • A=234,Z=90
  • A=228, Z=94
  • A=232, Z=
If half-life of a radioactive substance is 60 minutes, then the percentage decay in 4 hours is?
  • 50%
  • 71%
  • 85%
  • 93.7%
In the nuclear reaction : X(n,α)3Li7 the term X will be 3 
  • 5B10
  • 5B9
  • 5B11
  • 2He4
The relation between U(r) and r for diatomic molecule is given as U(r)=ar12br5
The energy of dissociation of the molecule if given as
  • b24a2
  • b24a
  • 4a2b2
  • 4ab2
The order of magnitude of radius of nucleus is ___________.
  • 1015m
  • 1015m
  • 1010m
  • 1010m
Fusion reactions take lace at high temperature because
  • atoms are ionized at high temperature
  • molecules break up at high temperature
  • nuclei break up at high temperature
  • kinetic energy is high enough to overcome repulsion between nuclei
In the options below which one of the isotope of the uranium can cause fission reaction?
  • U234
  • U235
  • U237
  • U238
O19F19+e+ˉv
In this decay, the rest mass energy of O19 and F19 are 17692.33 MeV and 17687.51 MeV respectively. The Q factor of the decay is :
  • 4.82 MeV
  • 7 MeV
  • 17.69 MeV
  • none of these
A parent nucleus m1p decays into a daughter nucleus D through α emission in the following way m1pD+α The subscript and superscript on the daughter nucleus D will be written as
  • mnD
  • m+4nD
  • m4nD
  • m4n2D
The appreciable radioactivity of uranium minerals is mainly due to:
  • An uranium isotope of mass number 235
  • A thorium isotope of mass number 232
  • Actinium
  • Radium
When two deuterium nuclei fuse together to form a tritium nucleus, we get a
  • neutron
  • deuteron
  • alpha particle
  • proton
If M0 is the mass of an oxygen isotope 8O17 , Mp and MN are the masses of a proton and a neutron respectively, the nuclear binding energy of the isotope is
  • 8Mpc2
  • (M0+8Mp+9MN)c2
  • M0c2
  • (M017MN)c2
Assume that a neutron breaks into a proton and an electron. The energy released during this process is
(Mass of neutron =1.6725×1027kg, Mass of proton =1.6725×1027kg ,Mass of electron =9×1031kg)
  • 0.50625MeV
  • 7.10 MeV
  • 6.30 MeV
  • 5.40 MeV
If the binding energy per nucleon in 73Li and He nuclei are 5.60MeV and 7.06MeV respectively, then in the reaction  p+37Li24 He, binding energy is
  • 39.2 MeV
  • 28.24 MeV
  • 17.28 MeV
  • 1.46 MeV
The binding energy per nucleon of deuteron (1H2) and helium nucleus (2He4) is 1.1MeV and 7MeV respectively. If two deuteron nuclei reacts to form a single helium nucleus, then the energy released is
  • 13.9MeV
  • 26.9MeV
  • 23.6MeV
  • 19.2MeV
The binding energy per nucleon for the parent nucleus is E1 and that for the daughter nuclei is E2.Then
  • E2=2E1
  • E1>E2
  • E2>E1
  • E1=2E2
In the options given below, let E denote the rest mass energy of a nucleus and n  a neutron. The correct option is 
  • E(23692U)>E(13753I)+E(9739Y)+2E(n)
  • E(23692U)<E(13753I)+E(9739Y)+2E(n)
  • E(23692U)<E(14056Ba)+E(9436Kr)+2E(n)
  • E(23692U)=E(14056Ba)+E(9436Kr)+2E(n)
If M is atomic weight , A is mass number then MAA represents :
  • Mass defect
  • Packing fraction
  • Binding energy
  • Chain reaction
41H12He4+2e++26MeV
The above reaction represents 
  • Fusion
  • Fission
  • β-decay
  • γ-decay
A nucleus with mass number 220 initially at rest emits an α-particle. lf the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the α-particle.
  • 4.4MeV
  • 5.4MeV
  • 5.6MeV
  • 6.5MeV
The β-decay process, discovered around 1900, is basically the decay of a neutron (n). In the laboratory, a proton (p) and an electron (e) are observed as the decay products of the neutron. Therefore, considering the decay of a neutron as a two-body decay process, it was predicted theoretically that the kinetic energy of the electron should be a constant. But experimentally, it was observed that the electron kinetic energy has a continuous spectrum. Considering a three-body decay process, i.e. np+e+¯ve, around 1930, Pauli explained the observed electron energy spectrum. Assuming the anti-neutrino (¯ve) to be massless and possessing negligible energy, and the neutron to be at rest, momentum and energy conservation principles are applied. From this calculation, the maximum kinetic energy of the electron is 0.8×106eV. The kinetic energy carried by the proton is only the recoil energy.
If the anti-neutrino had a mass of 3 eV/c2 (where c is the speed of light) instead of zero mass, what should be the range of the kinetic energy, K, of the electron?
  • 0K0.8×106eV
  • 3.0eVK0.8×106cV
  • 3.0eVK<0.8×106eV
  • 0K<0.8×106eV
Assume that the nuclear binding energy per nucleon (B/A) versus mass number (A) is as shown in the figure. Use this plot to choose the correct choice(s) given below.
32275.PNG
  • Fusion of two nuclei with mass numbers lying in the range of 1<A<50 will release energy
  • Fusion of two nuclei with mass numbers lying in the range of 51<A<100 will release energy
  • Fission of a nucleus lying in the mass range of 100<A<200 will release energy when broken into two equal fragments
  • Fission of a nucleus lying in the mass range of 200<A<260 will release energy when broken into two equal fragments
The nucleus finally formed in fusion of protons in proton-proton cycle is that of :
  • Heavy hydrogen
  • Carbon
  • Helium
  • Lithium
In the core of nuclear fusion reactor, the gas becomes plasma because of
  • strong nuclear force acting between the deuterons
  • Coulomb force acting between the deuterons
  • Coulomb force acting between deuteron-electron pairs
  • the high temperature maintained inside the reactor core
The source of stellar energy is 
  • Nuclear fission
  • Nuclear fusion
  • Nuclear fission & fusion
  • Nuclear decay
After losing two electrons, an atom of Helium becomes equivalent to
  • α -particle
  • β -particle
  • γ -particle
  • Deuterium nucleus
The Binding energy per nucleon of 73Li and 42He nucleon are 5.60MeV and 7.06MeV, respectively. In the nuclear reaction 73Li+11H42He+42He+Q, the value of energy Q released is
  • 19.6 MeV
  • 2.4 MeV
  • 8.4 MeV
  • 17.3 MeV
When a uranium isotope 23592U is bombarded with a neutron, it generates 8936Kr, three neutrons and :
  • 9140Zr
  • 10136Kr
  • 10336Kr
  • 14456Ba
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
\displaystyle { S }^{ 32 } absorbs energy and decays into which element after two \displaystyle \alpha -emissions?
  • Carbon
  • Aluminium
  • Oxygen
  • Magnesium
Find BE per nucleon of ^{56}Fe where m(^{56}Fe) = 55.936u\ m_{n} = 1.00727u, m_{p} = 1.007274\ u.
  • 477.45\ MeV
  • 8.52\ MeV
  • 577\ MeV
  • 10.52\ MeV
Which of the following is wrong statement about binding energy ?
  • It is the sum of the rest mass energies of nucleons minus the rest mass energy of the nucleus
  • It is the energy released when the nucleons combine to form a nucleus
  • It is the energy required to break a given nucleus into its constituent nucleons
  • It is the sum of the kinetic energies of all the nucleons in the nucleus
The difference between the mass of a nucleus and the combined mass of its nucleons is :
  • zero
  • positive
  • negative
  • zero, positive or negative
What parameter is used to measure the stability of a nucleus?
  • Average binding energy
  • No. of protons
  • No. of neutrons
  • No. of electrons
The binding energies of a deutron and an \alpha -particle are 1.125, 7.2 MeV/nucleon respectively. Which is more stable of the two?
  • deuteron
  • \alpha -practicle
  • both
  • sometimes deutron and sometimes \alpha -particle
What is the average binding energy per nucleon over a wide range ?
  • 8MeV
  • 8.8MeV
  • 7.6MeV
  • 1.1MeV
When the number of nucleons in a nucleus increases, the binding energy per nucleon :
  • increases continuously with mass number
  • decreases continuously with mass number
  • remains constant with mass number
  • first increases and then decreases with increase in mass number
Bombardment of Beryllium by alpha particles resulted in the discovery of :
  • Proton
  • Nucleus
  • Neutron
  • Positron
The short range attractive nuclear forces that are responsible for the binding of nucleons in a nucleus are supposed to be caused by the role played by the particles called
  • Positron
  • m-Meson
  • K-Meson
  • \pi - Meson
The percentage of mass lost during nuclear fusion is 
  • 0.1%
  • 0.4%
  • 0.5%
  • 0.65%
Fusion reactions take place at about :
  • 3\times 10^{2} K
  • 3\times 10^{3} K
  • 3\times 10^{4} K
  • 3\times 10^{6} K
In an endothermic reaction the binding energies of reactants and products are e_{1}, e_{2} respectively, then
  • e_{1}< e_{2}
  • e_{1}= e_{2}
  • e_{1}> e_{2}
  • e_{1} \geq e_{2}
If the nuclei of masses X and Y are fused together to form a nucleus of mass m and some energy is released, then 
  • X+Y=m
  • X+Y< m
  • X+Y> m
  • X-Y=m
The critical mass of a fissionable material is
  • 0.1 kg
  • the minimum mass needed for chain reaction
  • the rest mass equivalent to 1020 joules
  • 0.5 kg
In an energy emitting nuclear reaction the binding energies of reactants and products are  e_{1}, e_{2} respectively.Then which is  correct of the following ?
  • e_{1} < e_{2}
  • e_{1} = e_{2}
  • e_{1} > e_{2}
  • e_{1} \geq e_{2}
In carbon cycle of fusion, 4 protons combine to yield one alpha particle and
  • one positron
  • two positrons
  • ten positrons
  • three positrons
Why high temperature is required for Nuclear fusion ?
  • All nuclear reactions absorb heat
  • The particles can not come together unless they are moving rapidly
  • The binding energy must be supplied from an external source
  • The mass defect must be supplied
For a fast chain reaction, the size of U^{235} block, as compared to its critical size, must be
  • greater
  • smaller
  • same
  • anything
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