CUET Physics MCQs Unit VIII Atoms and Nuclei

CUET Physics Atoms MCQs

Question : Rutherford’s a-particle experiment showed that the atoms have
(a) Proton
(b) Nucleus
(c) Neutron
(d) Electrons

Answer: B

Question : In terms of Bohr radius r0, the radius of the second Bohr orbit of a hydrogen atom is given by
(a) 4 r0 
(b) 8 r0 
(c) 2 r0 
(d) 2 r0

Answer: A

Question : When an atomic gas or vapour is excited at low pressure, by passing an electric current through it then
(a) emission spectrum is observed
(b) absorption spectrucm is observed
(c) band spectrum is observed
(d) both (b) and (c)

Answer: A

Question : According to classical theory, the path of an electron in Rutherford atomic model is
(a) spiral
(b) circular
(c) parabolic
(d) straight line

Answer: A

Question : As the quantum number increases, the difference of energy between consecutive energy levels
(a) remain the same
(b) increases
(c) decreases
(d) sometimes increases and sometimes decreases.

Answer: C

Question : When hydrogen atom is in its first excited level, it’s radius is
(a) four times, it ground state radius
(b) twice times, it ground state radius
(c) same times, it ground state radius
(d) half times, it ground state radius.

Answer: A

Question : The first model of atom was proposed by
(a) Hans Geiger 
(b) Ernst Rutherford
(c) J.J. Thomson 
(b) N.H.D Bohr

Answer: C

Question : According to the Rutherford’s atomic model, the electrons inside the atom are
(a) stationary 
(b) not stationary
(c) centralized 
(d) None of these

Answer: B

Question : In Rutherford's α -particle scattering experiment, what will be correct angle for α scattering for an impact parameter b : 0 ?
(a) 90º 
(b) 270º 
(c) 0º 
(d) 180º

Answer: D

Question : In a Rutherford scattering experiment when a projectile of charge Z1 and mass M1approaches a target nucleus of charge Z2 and mass M2, the distance of closest approach is r0. The energy of the projectile is
(a) directly proportional to Z1 Z2
(b) inversely proportional to Z1
(c) directly proportional to mass M1
(d) directly proportional to M1 × M2

Answer: A

Question : As one considers orbits with higher values of n in a hydrogen atom, the electric potential energy of the atom
(a) decreases 
(b) increases
(c) remains the same 
(d) does not increase

Answer: B

Question : As the quantum number increases, the difference of energy between consecutive energy levels
(a) remain the same
(b) increases
(c) decreases
(d) sometimes increases and sometimes decreases.

Answer: C

Question : The angular momentum of the electron in hydrogen atom in the ground state is
(a) 2h 
(b) h/2
(c) h/2π
 (d) h/4π

Answer: C

Question : In Balmer series of emission spectrum of hydrogen, first four lines with different wavelength Hα Hβ Hγ and Hδ are obtained. Which line has maximum frequency out of these?
(a) Hα 
(b) Hβ 
(c) Hγ 
(d) Hδ

Answer: D

Question : As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion
(a) kinetic energy decreases, potential energy increases but total energy remains same
(b) kinetic energy and total energy decrease but potential energy increases
(c) its kinetic energy increases but potential energy and total energy decrease
(d) kinetic energy, potential energy and total energy decrease

Answer: C

Question : The transition from the state n : 4 to n : 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from
(a) 2 → 1 
(b) 3 → 2 
(c) 4 → 2 
(d) 5 → 4

Answer: D

Question : According to Bohr the difference between the energies of the electron in the two orbits is equal to
(a) hν 
(b) hc/λ
(c) both (a) and (b) 
(d) neither (a) nor (b)

Answer: C

Question : Which of the following are in the ascending order of wavelength?
(a) Hα, Hβ and Hγ lines of Balmer series
(b) Lyman limit, Balmer limit
(c) Violet, blue, yellow, red colours in solar spectrum
(d) both (b) and (c)

Answer: D

Question : Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr’s atomic model?
(a) 1.9 eV
(b) 11.1 eV
(c) 13.6 eV
(d) 0.65 eV

Answer: B

Question : Suppose potential energy between electron and proton at separation r is given by U : K ln (r), where K is a constant. For such a hypothetical hydrogen atom, the ratio of energy difference between energy levels (n : 1 and n : 2) and (n : 2 and n : 4) is
(a) 1
(b) 2
(c) 3
(d) 4

Answer: A

Question : When hydrogen atom is in its first excited level, it’s radius is 
(a) four times, it ground state radius
(b) twice times, it ground state radius
(c) same times, it ground state radius
(d) half times, it ground state radius

Answer: A

Question : When an electron jumps from the fourth orbit to the second orbit, one gets the
(a) second line of Paschen series
(b) second line of Balmer series
(c) first line of Pfund series
(d) second line of Lyman series

Answer: A

Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series 
(b) Balmer series
(c) Lyman series 
(d) Brackett series

Answer: B

Question : Bohr’s atom model is the modification of Rutherford’s atom model by the application of
(a) newton's theory 
(b) huygen’s theory
(c) maxwell’s theory 
(d) planck’s quantum theory

Answer: D

Question : According to Planck’s quantum theory any electromagnetic radiation is
(a) continuously emitted
(b) continuously absorbed
(c) emitted or absorbed in discrete units
(d) None of these

Answer: C

Question : The ionization energy of hydrogen atom is 13.6 eV. Following Bohr’s theory, the energy corresponding to a transition between 3rd and 4th orbit is
(a) 3.40 eV
(b) 1.51 eV
(c) 0.85 eV
(d) 0.66 eV

Answer: D

Question : The ratio of the energies of the hydrogen atom in its first to second excited states is
(a) 1/4
(b) 4/9
(c) 9/4
(d) 4

Answer: C

Question : An unknown hot gas emits radiation of wavelengths 46.0 nm, 82.8 nm and 103.5 nm only. Assume that the atoms have only two excited states and the difference between consecutive energy levels decreases as energy is increased. Taking the energy of the highest energy state to be zero, find the energies of the ground state and the first excited state.
(a) –27 eV, – 12 eV
(b) –6 eV, – 3 eV
(c) –11 eV, – 8 eV
(d) –9 eV, – 3 eV

Answer: A

Question : Rutherford’s atomic model was unstable because
(a) nuclei will break down
(b) electrons do not remain in orbit
(c) orbiting electrons radiate energy
(d) electrons are repelled by the nucleus

Answer: B

Question : The Balmer series for the H-atom can be observed
(a) if we measure the frequencies of light emitted when an excited atom falls to the ground state
(b) if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
(c) in any transition in a H-atom
(d) None of these

Answer: B

Question : The empirical atom model was given by
(a) J. J. Thomson 
(b) Rutherford
(c) Niels Bohr 
(d) Sommerfeld

Answer: A

Question : Rutherford’s α-particle experiment showed that the atoms have
(a) Proton 
(b) Nucleus
(c) Neutron 
(d) Electrons

Answer: B

Question : In the ground state in ...A... electrons are in stable equilibrium while in ...B... electrons always experiences a net force. Here, A and B refer to
(a) Dalton’s theory, Rutherford model
(b) Rutherford’s model, Bohr’s model
(c) Thomson’s model, Rutherford’s model
(d) Rutherford’s model, Thomson’s model

Answer: C

Question : Rutherford’s atomic model was unstable because
(a) nuclei will break down
(b) electrons do not remain in orbit
(c) orbiting electrons radiate energy
(d) electrons are repelled by the nucleus

Answer: B

Question : According to Bohr’s model of hydrogen atom
(a) the linear velocity of the electron is quantised.
(b) the angular velocity of the electron is quantised.
(c) the linear momentum of the electron is quantised.
(d) the angular momentum of the electron is quantised.

Answer: D

Question : The first spectral series was disscovered by
(a) Balmer 
(b) Lyman 
(c) Paschen 
(d) Pfund

Answer: B

Question : The shortest wavelength in Balmer’s series for Hydrogen atom is ...A... and this is obtained by substituting ...B ... in Balmer’s formula. Here, A and B refer to
(a) 656.3 nm, n : 3 
(b) 486.1 nm, n : 4
(c) 410.2 nm, n : 5 
(d) 364.6 nm, n :  

Answer: D

Question : In Bohr’s model electrons are revolving in a circular orbits around the nucleus called as
(a) stationary orbits 
(b) non radiating orbits
(c) Bohr’s orbits 
(d) all of these

Answer: D

Question : Rydberg’s constant is
(a) same for all elements
(b) different for different elements
(c) a universal constants
(d) is different for lighter elements but same for heavier elements

Answer: B

Question : Energy required for the electron excitation in Li++ from the first to the third Bohr orbit is
(a) 36.3 eV
(b) 108.8 eV
(c) 122.4 eV
(d) 12.1 eV

Answer: B

Question : According to Bohr’s model of hydrogen atom
(a) the linear velocity of the electron is quantised
(b) the angular velocity of the electron is quantised
(c) the linear momentum of the electron is quantised
(d) the angular momentum of the electron is quantised

Answer: D

Question : The Lyman transitions involve
(a) largest changes of energy
(b) smallest changes of energy
(c) largest changes of potential energy
(d) smallest changes of potential energy

Answer: A

Question : Electrons in the atom are held to the nucleus by
(a) coulomb’s force
(b) nuclear force
(c) vander waal’s force 
(d) gravitational force

Answer: A

Question : According to classical theory, Rutherford’s atomic model is
(a) stable 
(b) unstable
(c) meta stable 
(d) both (a) and (b)

Answer: D

Question : Which of the following in a hydrogen atom is independent of the principal quantum number n? (The symbols have their usual meanings).
(a) νn 
(b) Er
(c) En 
(d) νr

Answer: B

Question : In which of the following series, does the 121.5 nm line of the spectrum of the hydrogen atom lie ?
(a) Lyman series 
(b) Balmer series
(c) Paschen series 
(d) Brackett series.

Answer: A

Question : For a given value of n, the number of electrons in an orbit is
(a) n 
(b) n2 
(c) 2n2 
(d) 2n

Answer: C

Question : The largest wavelength in the ultraviolet region of the hydrogen spectrum is 122 nm. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is
(a) 802 nm
(b) 823 nm
(c) 1882 nm
(d) 1648 nm

Answer: B

Question : The Rutherford α-particle experiment shows that most of the α-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom? 
(a) Atom is hollow.
(b) The whole mass of the atom is concentrated in a small centre called nucleus
(c) Nucleus is positively charged
(d) All of the above

Answer: D

Question : Which of the following parameters is the same for all hydrogen-like atoms and ions in their ground states?
(a) Radius of the orbit
(b) Speed of the electron
(c) Energy of the atom
(d) Orbital angular momentum of the electron

Answer: D

Question : The Balmer series for the H-atom can be observed
(a) if we measure the frequencies of light emitted when an excited atom falls to the ground state
(b) if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
(c) in any transition in a H-atom
(d) None of these

Answer: B

Question : According to Bohr’s theory of H atom, an electron can revolve around a proton indefinitely, if its path is
(a) a perfect circle of any radius
(b) a circle of an allowed radius
(c) a circle of constantly decreasing radius
(d) an ellipse with fixed focus

Answer: B

Question : If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n : 2 is
(a) 10.2 eV
(b) 0 eV
(c) 3.4 eV
(d) 6.8 eV.

Answer: C

Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series
(b) Balmer series
(c) Lyman series
(d) Brackett series

Answer: B

Question : According to classical theory, the circular path of an electron in Rutherford atom model is
(a) spiral 
(b) circular
(c) parabolic 
(d) straight line

Answer: A

Question : The angular speed of the electron in the nth orbit of Bohr hydrogen atom is
(a) directly proportional to n
(b) inversely proportional to n
(c) inversely proportional to n2
(d) inversely proportional to n3

Answer: D

Question : In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
(a) n = 2 to n = 1 
(b) n = 3 to n = 1
(c) n = 4 to n = 2 
(d) n = 3 to n = 2

Answer: B

Question : In the hydrogen atom, an electron makes a transition from n : 2 to n : 1. The magnetic field produced by the circulating electron at the nucleus
(a) decreases 16 times
(b) increases 4 times
(c) decreases 4 times
(d) increases 32 times 

Answer: D

Question : In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
(a) n = 2 to n = 1
(b) n = 3 to n = 1
(c) n = 4 to n = 2
(d) n = 3 to n = 2

Answer: B

Question : Electrons in the atom are held to the nucleus by
(a) coulomb’s force 
(b) nuclear force
(c) vander waal’s force 
(d) gravitational force

Answer: C

Question : Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
(a) Paschen series 
(b) Balmer series
(c) Lyman series 
(d) Brackett series

Answer: B

Question : In Bohr model of hydrogen atom, let P.E. represents potential energy and T.E. represents the total energy. In going to a higher level.
(a) P. E. decreases, T.E. increases
(b) P. E. increases, T.E. decreases
(c) P. E. decreases, T.E. decreases
(d) P. E. increases, T.E. increases

Answer: D

Question : Which of the following statements is correct in case of Thomson’s atomic model?
(a) It explains the phenomenon of thermionic emission, photoelectric emission and ionisation.
(b) It could not explain emission of line spectra by elements.
(c) It could not explain scattering of α-particles
(d) All of the above

Answer: C

Question : The electrons of Rutherford’s model would be expected to lose energy because, they
(a) move randomly
(b) jump on nucleus
(c) radiate electromagnetic waves
(d) escape from the atom

Answer: C

Question : The angular momentum of electrons in an atom produces
(a) magnetic moment 
(b) ZEEMAN effect
(c) light 
(d) nuclear fission

Answer: A

Question : Which one did Rutherford consider to be supported by the results of experiments in which α-particles were scattered by gold foil?
(a) The nucleus of an atom is held together by forces which are much stronger than electrical or gravitational forces.
(b) The force of repulsion between an atomic nucleus and an α-particle varies with distance according to inverse square law.
(c) α-particles are nuclei of Helium atoms.
(d) Atoms can exist with a series of discrete energy levels

Answer: B

Question : Excitation energy of a hydrogen like ion in its excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is
(a) 54.4 eV
(b) 13.6 eV
(c) 40.8 eV
(d) 27.2 eV

Answer: A

Question : The significant result deduced from the Rutherford's scattering experiment is that
(a) whole of the positive charge is concentrated at the centre of atom
(b) there are neutrons inside the nucleus
(c) α-particles are helium nuclei
(d) electrons are embedded in the atom
(e) electrons are revolving around the nucleus

Answer: A

Question : Hydrogen atom excites energy level from fundamental state to n : 3. Number of spectral lines according to Bohr, is
(a) 4 
(b) 3 
(c) 1 
(d) 2

Answer: B
 

CUET Physics Nuclei MCQs

Question : Nucleus of an atom whose atomic mass is 24 consists of
(a) 11 electrons, 11 protons and 13 neutrons
(b) 11 electrons, 13 protons and 11 neutrons
(c) 11 protons and 13 neutrons
(d) 11 protons and 13 electrons

Answer: C

Question : Which of the following is not a mode of radioactive decay ?
(a) Positron emission 
(b) Electron capture
(c) Fusion 
(d) Alpha decay

Answer: C

Question : The constituents of nucleus are
(a) electrons and protons
(b) protons and neutrons
(c) neutrons and electrons
(d) electrons, protons and neutrons

Answer: B

Question : Nuclear forces are
(a) spin dependent and have no non-central part
(b) spin dependent and have a non-central part
(c) spin independent and have no non-central part
(d) spin independent and have a non-central part

Answer: D

Question : For a nuclear fusion process, suitable nuclei are
(a) any nuclei
(b) heavy nuclei
(c) lighter nuclei
(d) nuclei lying in the middle of periodic table

Answer: C

Question : Particles which can be added to the nucleus of an atom without changing its chemical properties are called
(a) neutrons 
(b) electrons
(c) protons 
(d) alpha particles

Answer: A

Question : A nuclei having same number of neutron but different number of protons / atomic number are called
(a) isobars 
(b) isomers
(c) isotones 
(d) isotopes

Answer: C

Question : Mass energy equation was propounded by
(a) Newton 
(b) Madam Curie
(c) C. V. Raman 
(d) Einstein

Answer: D

Question : Nuclear forces exists between
(a) neutron - neutron 
(b) proton - proton
(c) neutron - proton 
(d) all of these

Answer: D

Question : Beta rays emitted by a radioactive material are
(a) electromagnetic radiations
(b) the electrons orbiting around the nucleus
(c) charged particles emitted by nucleus
(d) neutral particles

Answer: C

Question : Artificial radioactivity was discovered by
(a) Klaproth 
(b) Rontgen
(c) Irene Curie and Joliot 
(d) P. Curie and M. Curie

Answer: C

Question : Which of the following of a radioactive material is a measure of its instability?
(a) Full life 
(b) Mean life
(c) Half life 
(d) None of these

Answer: C

Question : Charge on an α-particle is
(a) 1.6 × 10–19 C 
(b) 3.2 × 10–19 C
(c) 1.6 × 10–20 C 
(d) 4.8 × 10–19 C

Answer: B

Question : The 'rad' is the correct unit used to report the measurement of
(a) the ability of a beam of gamma ray photons to produce ions in a target
(b) the energy delivered by radiation to a target
(c) the biological effect of radiation
(d) the rate of decay of a radioactive source

Answer: C

Question : Control rods used in nuclear reactors are made of
(a) stainless steel 
(b) graphite
(c) cadmium 
(d) plutonium

Answer: C

Question : A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 a.m.u. The energy liberated per a.m.u. is (Given : 1 a.m.u = 931 MeV)
(a) 26.7 MeV
(b) 6.675 MeV
(c) 13.35 MeV
(d) 2.67 MeV

Answer: B

Question : A radioactive material undergoes decay by ejecting electrons. The electron ejected in this process is
(a) the electron from the decay of a neutron
(b) the electron present in the nucleus
(c) the resulting from the conversion of g photon
(d) an orbital electron

Answer: A

Question : A freshly prepared radioactive source of half life 2 hr emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is
(a) 6 hr
(b) 12 hr
(c) 24 hr
(d) 128 hr

Answer: B

Question : When the number of nucleons in nuclei increases, the binding energy per nucleon
(a) increases continuously with mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) first increases and then decreases with increase of mass number

Answer: D

Question : Chadwick was awarded the 1935 nobel prize in physics for his discovery of the
(a) electron
(b) proton
(c) neutron
(d) positron

Answer: C

Question : The electrons cannot exist inside the nucleus because
(a) de-Broglie wavelength associated with electron in β -decay is much less than the size of nucleus
(b) de-Broglie wavelength associated with electron in β -decay is much greater than the size of nucleus
(c) de-Broglie wavelength associated with electron in β -decay is equal to the size of nucleus
(d) negative charge cannot exist in the nucleus

Answer: B

Question : When the number of nucleons in nuclei increases, the binding energy per nucleon
(a) increases continuously with mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) first increases and then decreases with increase of mass number

Answer: D

Question : Nuclear forces are
(a) spin dependent and have no non-central part
(b) spin dependent and have a non-central part
(c) spin independent and have no non-central part
(d) spin independent and have a non-central part

Answer: B

Question : γ-rays are deflected by
(a) an electric field but not by a magnetic field
(b) a magnetic field but not by an electric field
(c) both electric and magnetic field
(d) neither by electric field nor by magnetic field

Answer: D

Question : The process of radioactive radiations remains unaffected due to
(a) physical changes
(b) chemical changes
(c) electric or magnetic fields
(d) all of the above

Answer: D

Question : Fusion reactions take place at high temperature because
(a) atoms are ionised at high temperature
(b) molecules break up at high temperature
(c) nuclei break up at high temperature
(d) kinetic enrgy is high enough to overcome repulsion between nuclei

Answer: D

Question : One curie is equal to
(a) 3.7 × 1010 disintegration/sec
(b) 3.2 × 108 disintegration/sec
(c) 2.8 × 1010 disintegration/sec
(d) None of these

Answer: A

Question : Boron rods in a nuclear reactor are used to
(a) absorb excess neutrons
(b) absorb alpha particle
(c) slow down the reaction
(d) speed up the reaction

Answer: A

Question : Radioactivity is
(a) irreversible process
(b) self disintegration process
(c) spontaneous
(d) all of the above

Answer: D

Question : Half life of radioactive element depends upon
(a) amount of element present
(b) temperature
(c) pressure
(d) nature of element

Answer: D

Question : On an average, the number of neutrons and the energy of a neutron released per fission of a uranium atom are respectively
(a) 2.5 and 2 keV
(b) 3 and l keV
(c) 2.5 and 2 MeV
(d) 2 and 2 keV

Answer: C

Question : The nuclear radius is of the order of
(a) 10–10 m
(b) 10–6 m
(c) 10–15 m
(d) 10–14 m

Answer: D

Question : The number of protons in an atom of atomic number Z and mass number A is
(a) zero 
(b) Z
(c) A – Z 
(d) A

Answer: B

Question : The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This implies that helium
(a) can easily be broken up
(b) is very stable
(c) can be used as fissionable meterial
(d) is radioactive

Answer: B

Question : The half-life period and the mean life period of a radioactive element are denoted respectively by Th and Tm. Then
(a) Th = Tm 
(b) Th > T m
(c) Th < Tm 
(d) Th ≥ Tm

Answer: C

Question : The rate of disintegration at a given instant, is directly proportional to the number of atoms present at that instant. This is the statement of
(a) law of radioactive decay
(b) half life
(c) law of radioactive transformation
(d) group displacement law

Answer: A

Question : Radioactive substance emits
(a) α-rays 
(b) β-rays
(c) γ-rays 
(d) All of the above

Answer: D

Question : A moderator is used in nuclear reactors in order to
(a) slow down the speed of the nuetrons
(b) acceleerate the neutrons
(c) increase the number of neutrons
(d) decrease the number of neutrons

Answer: C

Question :  Which of the following is not a mode of a radioactive decay ?
(a) Positron emission
(b) Electron capture
(c) Fusion               
(d) Alpha decay

Answer: C

Question : The radius of a nucleus is
(a) directly proportional to its mass number
(b) inversely proportional to its atomic weight
(c) directly proportional to the cube root of its mass number
(d) None of these

Answer: C

Question : Fusion reactions take place at high temperature because
(a) atoms are ionised at high temperature
(b) molecules break up at high temperature
(c) nuclei break up at high temperature
(d) kinetic enrgy is high enough to overcome repulsion between nuclei

Answer: D

Question : Which one of the following has the identical property for isotopes?
(a) Physical property
(b) Chemical property
(c) Nuclear property 
(d) Thermal property

Answer: B

Question : The antiparticle of electron is
(a) positron 
(b) α-particle
(c) proton 
(d) β-particle

Answer: D

Question : In γ ray emission from a nucleus
(a) only the proton number changes
(b) both the neutron number and the proton number change
(c) there is no change in the proton number and the neutron number
(d) only the neutron number changes

Answer: C

Question : The same radioactive nucleus may emit
(a) all the three α, β and γ one after another
(b) all the three α, β and γ radiations simultaneously
(c) only α and β simultaneously
(d) only one α, β and γ at a time

Answer: D

Question : Half life of radioactive element depends upon
(a) amount of element present
(b) temperature
(c) pressure
(d) nature of element

Answer: D

Question : If 200 MeV energy is released in the fission of a single U235 nucleus, the number of fissions required per second to produce 1 kilowatt power shall be (Given 1eV = 1.6 × 10–19 J)
(a) 3.125 × 1013
(b) 3.125 × 1014
(c) 3.125 × 1015
(d) 3.125 × 1016

Answer: A

Question : The mass of an atomic nucleus is less than the sum of the masses of its constituents. This mass defect is converted into
(a) heat energy
(b) light energy
(c) electrical energy
(d) energy which binds nucleons together

Answer: D

Question : In ...X... water is circulated though the reactor vessel and transfers energy to steam generator in the ...Y... Here, X and Y refer to
(a) primary loop, secondary loop
(b) reactor core, turbine
(c) secondary loop, primary loop
(d) turbine, reactor core

Answer: A

Question : Radioactivity is
(a) irreversible process
(b) self disintegration process
(c) spontaneous
(d) all of the above

Answer: D

Question : Three specimens A, B, C of same radioactive element has activities 1 microcurie, 1 rutherford and 1 becquerel respectively. Which specimen has maximum mass?
(a) A 
(b) B
(c) C 
(d) all have equal masses

Answer: B

Question : If a star can convert all the He nuclei completely into oxygen nuclei. The energy released per oxygen nuclei is [Mass of He nucleus is 4.0026 amu and mass of Oxygen nucleus is 15.9994 amu]
(a) 7.6 MeV   
(b) 56.12 MeV
(c) 10.24 MeV
(d) 23.9 MeV

Answer: C

Question : The radius of a nucleus is
(a) directly proportional to its mass number
(b) inversely proportional to its atomic weight
(c) directly proportional to the cube root of its mass number
(d) None of these

Answer: C

Question : The mass of an atomic nucleus is less than the sum of the masses of its constituents. This mass defect is converted into
(a) heat energy
(b) light energy
(c) electrical energy
(d) energy which binds nucleons together

Answer: D

Question : Radioactive samples are stored in lead boxes because it is
(a) heavy 
(b) strong
(c) good absorber 
(d) bad conductor

Answer: C

Question : For a nuclear fusion process, suitable nuclei are
(a) any nuclei
(b) heavy nuclei
(c) lighter nuclei
(d) nuclei lying in the middle of periodic table

Answer: C

Question : The rate of disintegration at a given instant, is directly proportional to the number of atoms present at that instant. This is the statement of
(a) law of radioactive decay
(b) half life
(c) law of radioactive transformation
(d) group displacement law

Answer: A

Question : A moderator is used in nuclear reactors in order to
(a) slow down the speed of the nuetrons
(b) acceleerate the neutrons
(c) increase the number of neutrons
(d) decrease the number of neutrons

Answer: C

Question : Which of the following statement is not true regarding Einsteins mass energy relation?
(a) Mass disappears to reappear as energy.
(b) Energy disappears to reappear as mass.
(c) Mass and energy are two different forms of the same entity.
(d) Mass and energy can never be related to each other.

Answer: D

Question : If a radioactive element is placed in an evacuated chamber, then the rate of radioactive decay will
(a) decrease 
(b) remains unchanged
(c) increase 
(d) none of these

Answer: B

Question : Beta rays emitted by a radioactive material are
(a) electromagnetic radiations
(b) the electrons orbiting around the nucleus
(c) charged particles emitted by nucleus
(d) neutral particles

Answer: C

Question : Mp denotes the mass of a proton and Mn that of a neutron.
A given nucleus, of binding energy B, contains Z protons and N neutrons. The mass M(N, Z) of the nucleus is given by (c is the velocity of light)
(a) M(N, Z) = NMn + ZMp + B/c2
(b) M(N, Z) = NMn + ZMp – Bc2
(c) M(N, Z) = NMn + ZMp + Bc2
(d) M(N, Z) = NMn + ZMp – B/c2

Answer: D

Question : The γ radiations are
(a) electromagnetic radiation with high energy
(b) electromagnetic radiation with low energy
(c) charged particles emitted by the nucleus
(d) electrons orbiting the nucleus

Answer: A

Question : A nuclei having same number of neutron but different number of protons / atomic number are called
(a) isobars
(b) isomers
(c) isotones
(d) isotopes

Answer: C

Question : Neutron decay in free space is given as follows 0n1 → 1H1 + -1e0 +[] Then the parenthesis [ ] represents a
(a) neutrino 
(b) photon
(c) antineutrino
(d) graviton

Answer: C

Question : Fusion reaction occurs at temperatures of the order of
(a) 103 K 
(b) 107 K 
(c) 10 K 
(d) 104 K

Answer: B

Question : The element gold has
(a) 16 isotopes 
(b) 32 isotopes
(c) 96 isotopes 
(d) 173 isotopes

Answer: B

Question : A radioactive material undergoes decay by ejecting electrons. The electron ejected in this process is
(a) the electron from the decay of a neutron
(b) the electron present in the nucleus
(c) the resulting from the conversion of γ photon
(d) an orbital electron

Answer: A