Atoms and Nuclei — practice questions

118 curated practice questions from Atoms and Nuclei (Physics JEE Main, NTA Exams) — 96 easy, 13 medium, 9 hard. Every question includes the final answer free; step-by-step worked solutions with a free account.

• The relationship between energy of a photon and its wavelength
• In the case of radio isotope the value of t 1 /2 and λ are identical in magnitude. The value is:
• Calculate the separation between the particles of a system in the ground state, the corresponding binding energy and…
• The de-Broglie wavelength of a molecule of thermal energy k B T (k B = Boltzmann constant and T = absolute…
• The below is a plot of binding energy per nucleon E b , against the nuclear mass M; A, B, C, D, E, F correspond to…
• The ratio of minimum to maximum wavelength in Balmer series is
• If M 0 is the mass of an oxygen isotope 8 O 17 , M p and and M n are the masses of a proton and a neutron…
• The wavelength of K α line for an element of atomic number 43 is λ. Then the wavelength of K α line for an element of…
• Photons of frequency v fall on a metal surface for which the threshold frequency is v 0 . Then,
• A free neutron decays into a proton but a free proton does not decay into a neutron. This is because
• Hydrogen ( 1 H 1 ), Deuterium ( 1 H 2 ), singly ionised Helium ( 2 He 4 ) + and doubly ionised lithium ( 3 Li 6 ) + +…
• In N 0 is the original mass of the substance of half-life period t 1/2 = 5yr, then the amount of substance left after…
• In a hydrogen atom the electron makes a transition from (n + 1) th level to the nth level. If n >> 1, the frequency of…
• Which of the following atoms has the lowest ionization potential ?
• The half life of 215 At is 100 µs. The time taken for the radioactivity of a sample of 215 At to decay to 1 16 th of…
• In the nuclear reaction, _ 1 ^ 2 H + _ 1 ^ 2 H 1 2 He + 1 n n , if the binding energy of deuteron is 2.23 MeV and the…
• The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually…
• A nuclear transformation is denoted by X ( n , ) _ 3 ^ 7 Li . Which of the following is the nucleus of element X ?
• The K α X–ray emission line of tungsten occurs at λ = 0.021 nm. The energy difference between K and L levels in this…
• What will be the relation between wavelength of photon and electron of same energy?
• Starting with a sample of pure 66 Cu, 7/8 of it decays into Zn in 15 min. The corresponding half-life is
• The binding energy per nucleon of deuteron ( _ 1 ^ 2 H ) and helium nucleus ( _ 2 ^ 4 He ) is 1.1 MeV and 7 MeV…
• Consider the following reaction _ 1 H ^ 2 + _ 1 H ^ 2 _ 2 He ^ 4 + Q If m ( 1 H 2 ) = 2.0141 u ; m ( 2 He 4 ) = 4.0024…
• An electron in the ground state of hydrogen has an angular momentum L 1 , and an electron in the first excited state of…
• On operating an X–ray tube at 1 kV. X–rays of minimum wavelength 6.22 Å are produced. If the tube is operated at 10 kV…
• Which of the following transitions in the hydrogen atom emit the photon of highest frequency ?
• The binding energy per nucleon of 16 O is 7.97 MeV and that of 17 O is 7.75 MeV. The energy in MeV required to remove a…
• The kinetic energy of an electron in the first orbit of H atom is 13.6 eV. The total energy of an electron in the…
• If elements with principal quantum number n > 4 were not allowed in nature, the number of possible elements would be :
• An atom bomb weighing 1 kg explodes releasing 9 × 10 13 joule of energy. What percentage of mass is converted into…
• The percentage of mass which changes into energy in fusion of hydrogen to form helium nucleus is of the order of Given…
• Find the binding energy per nucleon of 0^ 16 . Given, Mass of one atom of g ^ 16 =15.994915 a.m.u. Mass of proton…
• A fraction f 1 of a radioactive sample decays in one half life, and a fraction f 2 decays in one mean life
• C -14 undergoes B-decay. _ 5 ^ 14 C _ 7 ^ 14 ~N + _ -1 ^ 5 e . If 1 × 10 11 atoms of carbon disintegrate per minute per…
• A nuclear reaction containing U 235 produces 10 MW. Calculate the fission rate assuming that 200 MeV of useful energy…
• In a nuclear reactor the fast moving neutrons are slowed down by passing them through
• The binding energy of deutron is 2.2 MeV and that of 2 He 4 is 28 MeV. If two deutrons are fused to form one 2 He 4 …
• The ratio of the energies of the hydrogen atom in the first to the second excited state
• Energy released by fission of one atom of U _ 12 ^ 325 is 200 MeV. The number of fission required per sec to produce a…
• Radioactive element decays to form a stable nuclide, then the rate of decay of reactant ( dN dt ) will vary with time (…
• A nucleus n X m emits one alpha and two beta particles. The resulting nucleus is
• The de Broglie wavelength of a particle of mass m moving with a kinetic energy E is
• The net force between two nucleons 1 fm apart is F 1 if both are protons, F 2 if both are neutrons, and F 3 if one is a…
• The ratio of the radii of nuclei of _ 13 Al ^ 27 and _ 52 T e ^ 125 is approximately
• A 200 W sodium street lamp emits yellow light of wavelength 0.6 µm. Assuming it to be 25% efficient in converting…
• 6 C 12 absorbs an energetic neutron and emits a β particle. The resulting nucleus is
• In an X-ray tube electrons bombarding the target produce X-rays of minimum wavelength 1 What must be the energy of…
• The energy released by the fission of one uranium atom is 200 MeV. The number of fissions per second required to…
• Two nucleons are at a separation of one fermi. Protons have a charge of +1.6 10^ -19 c . The net nuclear force between…
• The energy of an electron in the first Bohr orbit of H-atom is -13.6 eV. The possible energy value(s) of the excited…
• The half-life period of a radioactive substance is 5 min. The amount of substance decayed in 20 min. will be
• Let v 1 be the frequency of the series limit of the Lyman series, v 2 be the frequency of the first line of the Lyman…
• When _ 3 ^ 7 Li nuclei are bombarded by proton, and the resultant nuclei are _ 4 ^ 8 Be , the emitted particle will be
• The volume occupied by an atom is greater than the volume of the nucleus by factor of about:
• When _ 12 U ^ 235 is bombarded with slow neutrons, the result is the formation of
• The ratio of areas between the electron orbits for the first excited state to the ground state for the hydrogen atom is
• Suppose an electron is attracted towards the origin by a force k/r, where k is a constant and r is the distance of the…
• The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about 9. The spectral…
• The K α X-ray emission line of Tungsten occurs at λ = 0.021 nm. The energy difference between K and L levels in its…
• Two identical, photocathodes receive light of frequencies f 1 and f 2 . If the velocities of the photoelectrons (of…
• The surface of the metal is illuminated with the light of 400 nm. The kientic energy of the ejected photoelectrons was…
• Density of nucleus ( ) is related to mass number (A) by
• Rn decays into Po by emitting an α–particle with half life of 4 days. A sample contains 6.4 × 10 10 atoms of Rn. After…
• The half-life of a radioactive substance is 20 min. The approximate time interval (t 2 – t 1 ) between the time t 2…
• An alpha nucleus of energy 1 2 m v^ 2 bombards a heavy nuclear target of change Ze. Then the distance of closest…
• Energy released by one atom of U ^ 235 is nearly 200 MeV. Then one gram of U 235 will release energy of
• If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from…
• The half life of radium is about 1600 years. Of 100 g of radium existing now, 25 g will remain unchanged after
• Electrons accelerated by potential V are diffracted from a crystal. If d = 1 Å and i = 30°, V should be about (h = 6.6…
• Half-lives of two radioactive substances A and B are respectively 20 minutes and 40 minutes. Initially the samples of A…
• An electron makes transition inside a hydrogen atom. The orbital angular momentum of the electron may change by
• Consider the following reaction _ 2 He ^ 4 + _ 5 ~B ^ 11 _ 7 ~N ^ 14 + O . The particle represented by the parenthesis…
• Consider α particles, β particles and γ-rays, each having an energy of 0.5 MeV. In increasing order of penetrating…
• An alpha nucleus of energy 1 2 m v^ 2 bombards a heavy nuclear target of charge Ze. Then the distance of closest…
• The work function of a metal is 4 eV. For the emission of photoelectrons of zero velocity from the metal surface, the…
• Energy levels A, B, C of a certain atom correspond to increasing values of energy i.e., E A B C . If λ 1 ,λ 2 ,λ 3 …
• The binding energy per nucleon of _ 1 ^ 7 Li and _ 2 ^ 4 He nuclei and 5.60 MeV and 7.06 MeV, respectively. In the…
• Two protons are kept at a separation of 40 a A . F n is the nuclear force and F e is the electrostatic force between…
• In the options given below, let E denote the rest mass energy of a nucleus and (n) a neutron. The correct option is
• A hydrogen atom emits a photon corresponding to an electron transition from n = 5 to n = 1. The recoil speed of…
• Energy required for the electron excitation in Li 2+ from the first to the third Bohr orbit is
• If radius of the _ 13 ^ 27 Al nucleus is estimated to be 3.6 fermi, then the radius of _ 52 ^ 125 Te nucleus be nearly
• Li nucleus has three protons and four neutrons. Mass of Li nucleus is 7.016005 amu. Mass of proton is 1.007277 amu. and…
• The wavelength of the first line of Lyman series of hydrogen is 1216 Å. The wavelength of the second line of the same…
• The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV and the stopping potential for a…
• The half life of radon is 3.8 days. After how many days will 1 10 th of the radon sample remain behind
• The half-life period of a radioactive element X is same as the mean life time of another radioactive element Y…
• The ratio of the wavelength of the first line of Lyman series to the first line of Balmer series is
• If the binding energy per nucleon in _ 1 ^ 7 Li and _ 2 ^ 4 He nuclei are 5.60 MeV and 7.06 MeV respectively, then in…
• Light of two different frequencies whose photons have energies 1 eV and 2.5 eV successively illuminate a metal of work…
• After Absorbing a slowly moving neutron of mass m N (momentum ~ 0) a nucleus of mass M breaks into two nuclei of masses…
• The wavelengths of K α X–rays of two metals ‘A’ and ‘B’ are 4 1875 R and 1 675 R respectively, where ‘R’ is Rydberg…
• If an electron has, orbital angular momentum quantum number l = 7, then it will have an orbital angular momentum equal…
• The half life of a radioactive element is 30 days, in 90 days the percentage of disintegrated part is :–
• Which one of the following graphs represents correctly the variation of photoelectric current (i) with intensity (I) of…
• It is proposed to use the nuclear fusion reaction: _ 1 H ^ 2 + _ 1 H ^ 2 _ 2 He ^ 4 in a nuclear reactor of 200 MW…
• The binding energy per nucleon of deuteron [1 H ^ 2 ] and helium atom (2 He ^ 4 ) is 1.1 MeV and 7 MeV respectively. If…
• The binding energy per nucleon for the parent nucleus is E 1 and that for the daughter nuclei is E 2 . Then
• Which of the following cannot be emitted by radioactive substances during their decay ?
• A radioactive isotope has a half life T years. How long will it take the activity to reduce to 1% of its original value…
• In any fission process the ratio mass of fission products mass of parent nucleus is:
• In a hydrogen like atom electron makes transition from an energy level with quantum number n to another with quantum…
• If the total binding energies of _ 1 ^ 2 H , 2^ 4 H , 25 ^ 56 Fe and 12^ 235 U nucleus are 2.22, 28.3, 492 and 1786 MeV…
• If the radius of 150 is 3 fermi then what is the radius of Pb _ 12 ^ 255 (in fermi)
• Photon of frequency v has a momentum associated with it. If c is the velocity of light, the momentum is
• The graph between the instantaneous concentration (N) of a radioactive element and time (t) is
• Consider the fission reaction _ 92 ^ 236 U X ^ 117 + Y ^ 117 + n + n i.e. two nuclei of same mass number 117 are found…
• If a star can convert all the He nuclei completely into oxygen nuclei, the energy released per oxygen nucleus is [Mass…
• The activity of a radioactive sample is measured as 9750 counts (minute) –1 at t = 0 and 975 counts (minute) –1 at t =…
• An element has binding energy of 8 eV/nucleon. If it has total binding energy of 128 eV then the number of nucleons are
• On bombarding U 235 by slow neutrons, 200 MeV energy is released. If the power output of atomic reactor is 1.6 MW, then…
• C 14 has half life 5700 years. At the end of 11400 years, the actual amount left is
• In Bohr’s Model of hydrogen atom. The ratio between the period of revolution of an electron in orbit of n = 1 to the…
• The wavelengths involved in the spectrum of deuterium ( _ 1 ^ 2 D ) are slightly different from that of hydrogen…
• If N t = N o e – λ t then number of disintegrated atoms between t 1 to t 2 ( t 2 > t 1 ) will be :–
• M p denotes the mass of a proton and M n denotes the mass of a neutron. A given nucleus of B.E. B contains Z protons…
• If energy released in the fission of one nucleus is 3.2 10^ -11 , then the number of nuclei required per second in a…
• For which of the following particles will it be most difficult to experimentally verify the de-Broglie relationship?

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