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
  • $$N \geqslant Z$$
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 ; $$_{92}U^{238}\rightarrow _{z}Th^{A}+_{2}He^{4}$$ 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 : $$X(n, \alpha)_3Li^7$$ the term $$X$$ will be 3 
  • $$_5 B ^{10}$$
  • $$_5B^9$$
  • $$_5B^{11}$$
  • $$_2He^4$$
The relation between $$U(r)$$ and r for diatomic molecule is given as $$U(r)=\dfrac{a}{r^{12}} - \dfrac{b}{r^5}$$
The energy of dissociation of the molecule if given as
  • $$\dfrac{b^2}{4a^2}$$
  • $$\dfrac{b^2}{4a}$$
  • $$\dfrac{4a^2}{b^2}$$
  • $$\dfrac{4a}{b^2}$$
The order of magnitude of radius of nucleus is ___________.
  • $$10^{-15} m$$
  • $$10^{15} m$$
  • $$10^{-10} m$$
  • $$10^{10} m$$
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?
  • $$U_{234}$$
  • $$U_{235}$$
  • $$U_{237}$$
  • $$U_{238}$$
$$O^{19}\longrightarrow F^{19}+e+\bar v$$
In this decay, the rest mass energy of $$O^{19}$$ and $$F^{19}$$ 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 $$^{m}_{1}p$$ decays into a daughter nucleus $$D$$ through $$\alpha$$ emission in the following way $$^{m}_{1}p\rightarrow D+\alpha$$ The subscript and superscript on the daughter nucleus $$D$$ will be written as
  • $$^{m}_{n}D$$
  • $$^{m+4}_{n}D$$
  • $$^{m-4}_{n}D$$
  • $$^{m-4}_{n-2}D$$
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 $$M_{0}$$ is the mass of an oxygen isotope $$_{8}O^{17}$$ , Mp and $$M_{N}$$ are the masses of a proton and a neutron respectively, the nuclear binding energy of the isotope is
  • $$8{M_p}c^2$$
  • $$(-M_{0}+8M_{p}+9M_{N})c^{2}$$
  • $$M_{0}c^{2}$$
  • $$(M_{0}-17M_{N})c^{2}$$
Assume that a neutron breaks into a proton and an electron. The energy released during this process is
(Mass of neutron $$=1.6725\times 10^{-27}  kg$$, Mass of proton $$=1.6725\times 10^{-27}  kg$$ ,Mass of electron $$=9\times 10^{-31}  kg$$)
  • $$0.50625$$$$\mathrm{MeV}$$
  • $$7.10$$ $$\mathrm{MeV}$$
  • $$6.30$$ $$\mathrm{MeV}$$
  • $$5.40$$ $$\mathrm{MeV}$$
If the binding energy per nucleon in $$_{7}^{}\textrm{3}Li$$ and He nuclei are $$5.60 MeV$$ and $$7.06 MeV$$ respectively, then in the reaction  $$p+_{3}^{}\textrm{7}Li\rightarrow _{2}^{}\textrm{4}$$ He, binding energy is
  • 39.2 MeV
  • 28.24 MeV
  • 17.28 MeV
  • 1.46 MeV
The binding energy per nucleon of deuteron $$(_{1}\mathrm{H}^{2})$$ and helium nucleus $$(_{2} \mathrm{He}^{4} )$$ is $$1.1 $$$$\mathrm{M}\mathrm{e}\mathrm{V}$$ and $$7$$$$\mathrm{M}\mathrm{e}\mathrm{V}$$ respectively. If two deuteron nuclei reacts to form a single helium nucleus, then the energy released is
  • $$13.9\mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$26.9 \mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$23.6 \mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$19.2 \mathrm{M}\mathrm{e}\mathrm{V}$$
The binding energy per nucleon for the parent nucleus is $$\mathrm{E}_{1}$$ and that for the daughter nuclei is $$\mathrm{E}_{2}$$.Then
  • $$\mathrm{E}_{2}=2\mathrm{E}_{1}$$
  • $$\mathrm{E}_{1}>\mathrm{E}_{2}$$
  • $$\mathrm{E}_{2}>\mathrm{E}_{1}$$
  • $$\mathrm{E}_{1}=2\mathrm{E}_{2}$$
In the options given below, let $$E$$ denote the rest mass energy of a nucleus and $$'n\ '$$ a neutron. The correct option is 
  • $$\mathrm{E}(_{92}^{236}\mathrm{U})>\mathrm{E}(_{53}^{137}\mathrm{I})+\mathrm{E}(_{39}^{97}\mathrm{Y})+2\mathrm{E}(\mathrm{n})$$
  • $$\mathrm{E}(_{92}^{236}\mathrm{U})<\mathrm{E}(_{53}^{137}\mathrm{I})+\mathrm{E}(_{39}^{97}\mathrm{Y})+2\mathrm{E}(\mathrm{n})$$
  • $$\mathrm{E}(_{92}^{236}\mathrm{U})<\mathrm{E}(_{56}^{140} \mathrm{B}\mathrm{a} )+\mathrm{E}(_{36}^{94} \mathrm{K}\mathrm{r} )+2\mathrm{E}(\mathrm{n})$$
  • $$\mathrm{E}(_{92}^{236}\mathrm{U})=\mathrm{E}(_{56}^{140} \mathrm{B}\mathrm{a} )+\mathrm{E}(_{36}^{94} \mathrm{K}\mathrm{r} )+2\mathrm{E}(\mathrm{n})$$
If $$M$$ is atomic weight , $$A$$ is mass number then $$\dfrac{M-A}{A}$$ represents :
  • Mass defect
  • Packing fraction
  • Binding energy
  • Chain reaction
$$4_{1}H^{1} \rightarrow  _{2}He^{4}+2e^{+}  + 26 MeV$$
The above reaction represents 
  • Fusion
  • Fission
  • $$\beta$$-decay
  • $$\gamma$$-decay
A nucleus with mass number $$220$$ initially at rest emits an $$\alpha$$-particle. lf the $$\mathrm{Q}$$ value of the reaction is $$5.5 $$ $$\mathrm{M}\mathrm{e}\mathrm{V}$$, calculate the kinetic energy of the $$\alpha$$-particle.
  • $$4.4 \mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$5.4 \mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$5.6 \mathrm{M}\mathrm{e}\mathrm{V}$$
  • $$6.5 \mathrm{M}\mathrm{e}\mathrm{V}$$
The $$\beta$$-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. $$n\rightarrow p+e^{-}+\overline{v}_{e}$$, around 1930, Pauli explained the observed electron energy spectrum. Assuming the anti-neutrino $$(\overline{v}_{e})$$ 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 $$0.8\times 10^{6}eV$$. The kinetic energy carried by the proton is only the recoil energy.
If the anti-neutrino had a mass of 3 $$eV/c^{2}$$ (where $$c$$ is the speed of light) instead of zero mass, what should be the range of the kinetic energy, $$K$$, of the electron?
  • $$0\leq K\leq 0.8\times 10^{6}eV$$
  • $$3.0 eV\leq K\leq 0.8\times 10^{6}cV$$
  • $$3.0 eV \leq K<0.8\times 10^{6}eV$$
  • $$0\leq K<0.8\times 10^{6}eV$$
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
  • $$\alpha $$ -particle
  • $$\beta $$ -particle
  • $$\gamma $$ -particle
  • Deuterium nucleus
The Binding energy per nucleon of $$^7_3Li$$ and $$_2^4He$$ nucleon are $$5.60 MeV$$ and $$7.06 MeV$$, respectively. In the nuclear reaction $$_3^7Li+_1^1H\rightarrow _2^4He+^4_2He+Q$$, the value of energy $$Q$$ released is
  • $$19.6\ MeV$$
  • $$-2.4\ MeV$$
  • $$8.4\ MeV$$
  • $$17.3\ MeV$$
When a uranium isotope $$^{235}_{92}U$$ is bombarded with a neutron, it generates $$^{89}_{36}Kr$$, three neutrons and :
  • $$^{91}_{40}Zr$$
  • $$^{101}_{36}Kr$$
  • $$^{103}_{36}Kr$$
  • $$^{144}_{56}Ba$$
  • 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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