Q.1
) Excited hydrogen atom emits a photon of wave length in return to the groundstate The quantum number n of excited state is given by
  • a)
    ch-19_qn-191choice_img_no1.png
  • b)
    ch-19_qn-191choice_img_no2.png
  • c)
    ch-19_qn-191choice_img_no3.png
  • d)λR(R-1)
Q.2
) The radius of hydrogen atom in the first excited level is{AIIMS 1998}
  • a) Twice
  • b) four times
  • c) same
  • d) half
Q.3
Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is … [NEET 2013]
  • a) 5/27
  • b) 3/23
  • c) 7/29
  • d) 9/31
Q.4
The half life of a radioactive isotope ‘X’ is 20 years.It decays to another element ‘Y’ which is stable. Thetwo elements ‘X’ and ‘Y’ were found to be in theratio 1 : 7 in a sample of a given rock. The age ofthe rock is estimated to be…[NEET 2013]
  • a) 40 years
  • b) 60 years
  • c) 80 years
  • d) 100 years
Q.5
A certain mass of Hydrogen is changed to Heliumby the process of fusion. The mass defect in fusionreaction is 0.02866 u. The energy liberated per u is…[NEET 2013] (given 1 u = 931 MeV)
  • a) 2.67 MeV
  • b) 26.7 MeV
  • c) 6.675 MeV
  • d) 13.35 MeV
Q.6
The binding energy per nucleon of 3Li7 and 2He4 nuclei are 5.60 MeV and 7.06 MeV, Respectively. In the nuclear reaction the value of energy Q released ….
ch-19_que_no-196_img_no1.png
  • a) 8.4 MeV
  • b) 17.3 MeV
  • c) 19.6 MeV
  • d) – 2.4 MeV
Q.7
A radio isotope 'X' with a half life 1.4 × 109years decays to 'Y'which is stable.Asampleof the rock froma cavewas found to contain'X' and 'Y' in the ratio 1:The age of therock is[ AIPMT 2014]
  • a) 4.20 × 109 years
  • b) 8.40 × 109 years
  • c) 1.96 × 109 years
  • d) 3.92 × 109 years
Q.8
Hydrogen atom is ground state is excited by amonochromatic radiation of λ=975 Å.Number of spectral lines in the resulting spectrum emitted will be
  • a) 6
  • b) 10
  • c) 3
  • d) 2
Q.9
If radius of 13Al27 nucleus is taken to be RAl, then the radius of 53Te125 nucleus is nearly … [AIPMT 2015]
  • a)
    ch-19_qn-199choice_img_no1.png
  • b)
    ch-19_qn-199choice_img_no2.png
  • c)
    ch-19_qn-199choice_img_no3.png
  • d)
    ch-19_qn-199choice_img_no4.png
Q.10
In the spectrum of hydrogen, the ratio of the longestwavelength in the Lyman series to the longest wavelength in the Balmer series is : ..[ Re-AIPMT 2015]
  • a) 5/27
  • b) 4/9
  • c) 9/4
  • d) 27/5
Q.11
A nucleus of uranium decays at rest into nuclei ofthorium and helium. Then :-
  • a) The helium nucleus has less kinetic energy thanthe thorium nucleus
  • b) The helium has more kinetic energy than thethorium nucleus.
  • c) The helium nucleus has less momentum than thethorium nucleus.
  • d) The helium nucleus has more momentum thanthe thorium nucleus.
Q.12
When an α-particle of mass 'm' moving with velocity'v' bombards on a heavy nucleus of charge 'Ze', its distance of closest approach from the nucleusdepends on m as :
  • a) 1/m
  • b) 1/√m
  • d) m
  • c) 1/m²
Q.13
Given the value of Rydberg constant is 107m–1, thewave number of the last line of the Balmer series in hydrogen spectrum will be :-
  • a) 0.025 × 104 m–1
  • b) 0.5 × 107 m–1
  • c) 0.25 × 107 m–1
  • d) 2.5 × 107 m–1
Q.14
If an electron in a hydrogen atom jumps from the3rd orbit to the 2nd orbit, it emits a photon ofwavelength λ. When it jumps from the 4th orbit tothe 3rd orbit, the corresponding wavelength of thephoton will be …[NEET II -2016]
  • a) 20λ /7
  • b) 20λ /13
  • c) 16λ /25
  • d) 9λ /16
Q.15
The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is …[ NEET II – 2016]
  • a) 45
  • b) 60
  • c) 15
  • d) 30
Q.16
Radioactive material 'A' has decay constant '8λ' andmaterial 'B' has decay constant 'λ'. Initially they havesame number of nuclei. After what time, the ratio ofnumber of nuclei of material 'A' to that 'B' will be 1/e
  • a) ) 1/λ
  • b) 1/7λ
  • c) 1/8λ
  • d) 1/9λ
Q.17
The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is
  • a) 2
  • b) 1
  • c) 4
  • d) 0.5
Q.18
In a hydrogen like atom electron makes transition from an energy level with quantum number nto another with quantum number (n − 1). If n >> 1, the frequency of radiation emitted is proportional to …[ IIT Mains 2013]
  • a) 1/n
  • c) 1/n3/2
  • b) 1/n²
  • d) 1/n³
Q.19
The radius of the orbit of an electron in a Hydrogen-like atom is 4.5 a0, where a0 is the Bohr radius. Its orbital angular momentum is 3h/2π. It is given that h is Planck constant and R is Rydberg constant. The possible wavelength(s), when the atom de-excites, is (are)
  • a) 9/32R
  • b) 9/16R
  • c) 9/5R
  • d) 4/3R
Q.20
) Paragraph The mass of a nucleus ZXA is less than the sum of the masses of (A-Z) number of neutronsand Z number of protons in the nucleus. The energy equivalent to the corresponding massdifference is known as the binding energy of the nucleus. A heavy nucleus of mass M canbreak into two light nuclei of masses m1 and m2 only if (m1 + m2) < M. Also two light nucleiof masses m3 and m4 can undergo complete fusion and form a heavy nucleus of mass M′ only if (m3 + m4) > M′. The masses of some neutral atoms are given in the table below : The correct statement is
1H1 1.007825 u 1H2 2.014102 u
1H3 3.016050u 2He4 4.002603u
3Li6 6.015123 u 3Li7 7.016004 u
30Zn70 69.925325u 34Se82 81.916709u
64Gd152 151.919803u 82Pb206 205.974455u
83Bi209 208.980388u 84Po210 209.982876u
  • a) The nucleus 3Li6 can emit an alpha particle.
  • b) The nucleus 84Po210 can emit a proton.
  • c) Deuteron and alpha particle can undergo complete fusion.
  • d) The nuclei 30Zn70 and 34Se82 can undergo complete fusion
Q.21
The kinetic energy (in keV) of the alpha particle, when the nucleus 84Po210 at restundergoes alpha decay, is
  • a) 5319
  • b) 5422
  • c) 5707
  • d) 5818
Q.22
Match List I of the nuclear processes with List II containing parent nucleus and one of the end products of each process and then select the correct answer using the codes given below the lists:
List I List II
P. Alpha decay 8O15 → 7N15+ ....
Q. β+ decay 92U238 → 90Th234+ ....
R. Fission 83Bi185 → 82Pb184+ ....
S. Proton emission 94Pu239 → 57La140+ ...
  • a) P → 4 Q → 2 R → 1 S → 3
  • b) P → 1 Q → 3 R → 2 S → 4
  • c) P → 2 Q → 1 R → 4 S → 3
  • d) P → 4 Q → 3 R → 2 S→ 1
Q.23
)If λCu is the wavelength of Kα X-ray line of copper (atomic number 29) and λMo is the wavelength of the Kα X-ray line of molybdenum (atomic number 42), then the ratio λCu /λMo is close to
  • a) 1.99
  • b) 2.14
  • c) 0.50
  • d) 0.48
Q.24
A fission reaction is given by 92U236→ 54Xe140 + 38Sr94+x+y,where x and y are two particles. Considering 92U236 to be at rest, the kinetic energies of the products are denoted by KXe, KSr, Kx (2 MeV) and Ky (2 MeV), respectively. Let the binding energies per nucleon of 92U236,54Xe140,38Sr94 be 7.5 MeV, 8.5 MeV and 8.5 MeV, respectively. Considering different conservation laws, the correct option(s) is (are)
  • a) x = n, y = n, KSr = 129 MeV, KXe = 86 MeV
  • b) x = p, y = e, KSr = 129 MeV, KXe = 86 MeV
  • c) x = p, y = n, KSr = 129 MeV, KXe = 86 MeV
  • d) x = n, y = n, KSr = 86 MeV, KXe = 129 MeV
Q.25
Highly excited states for hydrogen-like atoms (also called Rydberg states) with nuclear charge Ze are defined by their principal quantum number n, where n >>Which of the following statement(s) is(are) true? [ IIT Advance 2016]
  • a) Relative change in the radii of two consecutive orbitals does not depend on Z
  • b) Relative change in the radii of two consecutive orbitals varies as 1/n
  • c) Relative change in the energy of two consecutive orbitals varies as 1/n3
  • d) Relative change in the angular momenta of two consecutive orbitals varies as 1/n
Q.26
P is the probability of finding the 1s electron of hydrogen atom in a spherical shell of infinitesimal thickness, dr, at a distance r from the nucleus. The volume of this shell is 4πr2 dr. The qualitative sketch of the dependence of P on r is… [ IIT Advance 2016]
  • a)
    ch-19_qn-225choice_img_no1.png
  • b)
    ch-19_qn-225choice_img_no2.png
  • c)
    ch-19_qn-225choice_img_no3.png
  • d)
    ch-19_qn-225choice_img_no4.png
Q.27
The electrostatic energy of Z protons uniformly distributed throughout a spherical nucleus of radius R is given by The measured masses of the neutron , 1H1, 7N15 and 8O15, are 1.008665 u, 1.007825 u, 15.000109 u and 15.003065 u, respectively. Given that the radii of both the and nuclei are same, 1 u = 931.5 MeV/c2 (c is the speed of light) and e2/(4πε0 ) = 1.44 MeVfm Assuming that the difference between the binding energies of 7N15 and 8O15 is purely due to the electrostatic energy, the radius of either of the nuclei is …[IIT Advance 2016] (1 fm = 10-15 m)
ch-19_que_no-226_img_no1.png
  • a) 2.85 fm
  • b) 3.03 fm
  • c) 3.42 fm
  • d) 3.80 fm
Q.28
An accident in a nuclear laboratory resulted in deposition of a certain amount of radioactive material of half-life 18 days inside the laboratory. Tests revealed that the radiation was 64 times more than the permissible level required for safe operation of the laboratory. What is the minimum number of days after which the laboratory can be considered safe for use? [IIT Advance 2016]
  • a) 64
  • b) 90
  • c) 108
  • d) 120
Q.29
The radius of hydrogen atom in its ground state is 5.3×10⁻¹¹ m. After collision with an electron it is found o have a radius of 21.2×10⁻¹¹ m. What is the principal quantum number n of the final state of the atom.. [ CBSE-PMT 1994]
  • a) n=4
  • b) n=2
  • c)n=16
  • d)n=3
Q.30
) Light form the discharge tube containing hydrogen atom falls on the surface of a Piece of sodium. The kinetic energy of the fastest photo electrons emitted form sodium is 0.73 eV. The work function for sodium is 1.82 eV. Ionigation Potential of hydrogen is 13.6 v and the mass of hydrogen atom is 1.67× 10⁻²⁷ kg. The energy of Photon causing the Photo electeic emission is
  • a) 4.08 × 10⁻¹⁹ J
  • b) 2.912 × 10⁻¹⁹
  • c)1.744 × 10⁻¹⁹
  • d)1.168 × 10⁻¹⁹
0 h : 0 m : 1 s