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Atoms and Nuclei

140 Questions
All Exams NEET AIIMS
2016 NEET MCQ
NEET 2016 Phase 1
When an $\alpha $-particle of mass m moving with velocity v bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as
A.
${1 \over {{m^2}}}$
B.
m
C.
${1 \over m}$
D.
${1 \over {\sqrt m }}$
2016 NEET MCQ
NEET 2016 Phase 1
Given the value of Rydberg constant is 107 m$-$1, the wave number of the last line of the Balmer series in hydrogen spectrum will be
A.
0.25 $ \times $ 107 m$-$1
B.
2.5 $ \times $ 107 m$-$1
C.
0.025 $ \times $ 104 m$-$1
D.
0.5 $ \times $ 107 m$-$1
2015 NEET MCQ
AIPMT 2015
In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is
A.
${{27} \over 5}$
B.
${5 \over {27}}$
C.
${4 \over 9}$
D.
${9 \over 4}$
2015 NEET MCQ
AIPMT 2015
A nucleus of uranium decays at rest into nuclei of thorium and helium. Then
A.
The helium nucleus has more momentum than the thorium nucleus.
B.
The helium nucleus has less kinetic energy than the thorium nucleus.
C.
The helium nucleus has more kinetic energy than the thorium nucleus.
D.
The helium nucleus has less momentum than the thorium nucleus.
2015 NEET MCQ
AIPMT 2015 Cancelled Paper
Consider 3rd orbit of He+ (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 $ \times $ 109 constant, Z = 2 and h (Planck's Constant) = 6.6 $ \times $ 10$-$34 J s]
A.
0.73 $ \times $ 106 m/s
B.
3.0 $ \times $ 108 m/s
C.
2.92 $ \times $ 106 m/s
D.
1.46 $ \times $ 106 m/s
2015 NEET MCQ
AIPMT 2015 Cancelled Paper
If radius of the ${}_{13}^{27}$ Al nucleus is taken to be RAl, then
the radius of ${}_{53}^{125}$Te nucleus is nearly
A.
${3 \over 5}{R_{Al}}$
B.
${\left( {{{13} \over {53}}} \right)^{1/3}}{R_{Al}}$
C.
${\left( {{{53} \over {13}}} \right)^{1/3}}{R_{Al}}$
D.
${5 \over 3}{R_{Al}}$
2014 NEET MCQ
AIPMT 2014
Hydrogen atom in ground state is excited by a monochromatic radiation of $\lambda $ = 975 $\mathop A\limits^ \circ $. Number of spectral lines in the resulting spectrum emitted will be
A.
3
B.
2
C.
6
D.
0 10
2014 NEET MCQ
AIPMT 2014
The binding energy per nucleon of and nuclei are 5.60 MeV and 7.06 MeV respectively. In the nuclear reaction

${}_3^7Li + {}_1^1H \to {}_2^4He + _2^4He + Q$

the value of energy Q released is
A.
19.6 MeV
B.
$-$ 2.4 MeV
C.
8.4 MeV
D.
17.3 MeV
2014 NEET MCQ
AIPMT 2014
A radioactive X with a half life 1.4 $ \times $ 109 years decays to Y which is stable. A sample of the rock from a cave was found to contain X and Y in the ratio 1 : 7. The age of the rock is
A.
1.96 $ \times $ 109 years
B.
3.92 $ \times $ 109 years
C.
4.20 $ \times $ 109 years
D.
8.40 $ \times $ 109 years
2013 NEET MCQ
NEET 2013 (Karnataka)
$\alpha $-particles, $\beta $-particles and $\gamma $-rays are all having same energy. Their penetrating power in a given medium in increasing order will be
A.
$\gamma $, $\alpha $, $\beta $
B.
$\alpha $, $\beta $, $\gamma $
C.
$\beta $, $\alpha $, $\gamma $
D.
$\beta $, $\gamma $, $\alpha $
2013 NEET MCQ
NEET 2013 (Karnataka)
An electron in hydrogen atom makes a transition n1 $ \to $ n2 where n1 and n2 are principal quantum numbers of the two states . Assuming Bohr's model to be valid, the time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are
A.
n1 = 6 and n2 = 2
B.
n1 = 8 and n2 = 1
C.
n1 = 8 and n2 = 2
D.
n1 = 4 and n2 = 2
2013 NEET MCQ
NEET 2013 (Karnataka)
How does the Binding Energy per nucleon vary with the increase in the number of nucleons ?
A.
Decrease continuously with mass number.
B.
First decreases and then increases with increase in mass number.
C.
First increases and then decreases with increase in mass number.
D.
increases continuously with mass number.
2013 NEET MCQ
NEET 2013
Ratio of longest wave lengths corresponding to Lyman and Balmer series in hydrogen spectrum is
A.
${7 \over {29}}$
B.
${9 \over {31}}$
C.
${5 \over {27}}$
D.
${3 \over {23}}$
2013 NEET MCQ
NEET 2013
A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is (given 1 u = 931 MeV)
A.
6.675 MeV
B.
13.35 MeV
C.
2.67 MeV
D.
26.7 MeV
2013 NEET MCQ
NEET 2013
The half life of a radioactive isotope 'X' is 20 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be
A.
80 years
B.
100 years
C.
40 years
D.
60 years
2012 NEET MCQ
AIPMT 2012 Mains
The half life of a radioactive nucleus is 50 days. The time invertal (t2 $-$ t1) between the time t2 when ${2 \over 3}$ of it has decayed and the time t1 when ${1 \over 3}$ of it had decayed is
A.
30 days
B.
50 days
C.
60 days
D.
15 days
2012 NEET MCQ
AIPMT 2012 Mains
The transition from the state n = 3 to n = 1 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from
A.
2 $ \to $ 1
B.
3 $ \to $ 2
C.
4 $ \to $ 2
D.
4 $ \to $ 3
2012 NEET MCQ
AIPMT 2012 Prelims
An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be
A.
${{24hR} \over {25m}}$
B.
${{25hR} \over {24m}}$
C.
${{25m} \over {24hR}}$
D.
${{24m} \over {25hR}}$
2012 NEET MCQ
AIPMT 2012 Prelims
Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths $\lambda $1 : $\lambda $2 emitted in the two cases is
A.
${7 \over 5}$
B.
${27 \over 20}$
C.
${27 \over 5}$
D.
${20 \over 7}$
2012 NEET MCQ
AIPMT 2012 Prelims
A mixture consists of two radioactive materials A1 and A2 with half lives of 20 s and 10 s respectively. Initially the mixture has 40 g of A1 and 160 g of A2. The amount of the two in the mixture will become equal after
A.
60 s
B.
80 s
C.
20 s
D.
40 s
2012 NEET MCQ
AIPMT 2012 Prelims
If the nuclear radius of 27Al is 3.6 fermi, the approximate nuclear radius of 64Cu in fermi is
A.
2.4
B.
1.2
C.
4.8
D.
3.6
2011 NEET MCQ
AIPMT 2011 Mains
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.
0.65 eV
B.
1.9 eV
C.
11.1 eV
D.
13.6 eV
2011 NEET MCQ
AIPMT 2011 Mains
Two radioactive nuclei P and Q, in a given sample decay into a stable nucleus R. At time t = 0. number of P species are 4 N0 and that of Q are N0. Half -life of P (for conversion to R) is 1 minute where as that of Q is 2 minutes. Initially there are no nuclei of R present in the sample. When number of nuclei of P and Q are equal, the number of nuclei of R present in the sample would be
A.
2 N0
B.
3 N0
C.
${{9{N_0}} \over 2}$
D.
${{5{N_0}} \over 2}$
2011 NEET MCQ
AIPMT 2011 Mains
An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photoelectron is 10 V, then the value of n is
A.
2
B.
3
C.
4
D.
5
2011 NEET MCQ
AIPMT 2011 Prelims
The half life of a radioactive isotope X is 50 years. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio of 1 : 15 in a sample of a given rock. The age of the rock was estimated to be
A.
150 years
B.
200 years
C.
250 years
D.
100 years
2011 NEET MCQ
AIPMT 2011 Prelims
The power obtained in a reactor using U235 disintegration is 1000 kW. The mass decay of U235 per hour is
A.
10 microgram
B.
20 microgram
C.
40 microgram
D.
1 microgram
2011 NEET MCQ
AIPMT 2011 Prelims
A radioactive nucleus of mass M emits a photon of frequency $v$ and the nucleus recoils. The recoil energy will be
A.
Mc2 $-$ h$v$
B.
h2$\upsilon $2/2Mc2
C.
zero
D.
h$v$
2011 NEET MCQ
AIPMT 2011 Prelims
The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is
A.
3
B.
4
C.
1
D.
2
2011 NEET MCQ
AIPMT 2011 Prelims
Fusion reaction takes place at high temperature because
A.
nuclei break up at high temperature
B.
atoms get ionised at high temperature
C.
kinetic energy is high enough to overcome the coulomb repulsion between nuclei
D.
molecules break up at high temperature
2011 NEET MCQ
AIPMT 2011 Prelims
A nucleus ${}_n^mX$ emits one $\alpha $ particle and two $\beta $ particles. The resulting nucleus is
A.
${}_{n - 4}^{m - 6}Z$
B.
${}_n^{m - 6}Z$
C.
${}_n^{m - 4}X$
D.
${}_{n - 2}^{m - 4}Y$
2010 NEET MCQ
AIPMT 2010 Mains
The decay constant of a radio isotope is $\lambda $. If A1 and A2 are its activities at times t1 and t2 respectively, the number of nuclei which have decayed during the time (t1 $-$ t2)
A.
A1t1 $-$ A2t2
B.
A1 $-$ A2
C.
(A1 $-$ A2)/$\lambda $
D.
$\lambda ({A_1} - {A_2})$
2010 NEET MCQ
AIPMT 2010 Mains
The binding energy per nucleon in deuterium and helium nuclei are 1.1 MeV and 7.0 MeV, respectively. When two deuterium nuclei fuse to form a helium nucleus the energy released in the fusion is
A.
23.6 MeV
B.
2.2 MeV
C.
28.0 MeV
D.
30.2 MeV
2010 NEET MCQ
AIPMT 2010 Prelims
The activity of a radioactive sample is measured as N0 counts per minute at t = 0 and N0/e counts per minute at t = 5 minutes. The time (in minutes) at which the activity reduces to half its value is
A.
${\log _e}{2 \over 5}$
B.
${5 \over {{{\log }_e}2}}$
C.
5log102
D.
5loge 2
2010 NEET MCQ
AIPMT 2010 Prelims
An alpha nucleus of energy ${1 \over 2}$ mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to
A.
${1 \over {Ze}}$
B.
v2
C.
${1 \over m}$
D.
${1 \over {{v_4}}}$
2010 NEET MCQ
AIPMT 2010 Prelims
The mass of a ${}_3^7Li$ Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of ${}_3^7Li$ nucleus is nearly
A.
46 MeV
B.
5.6 MeV
C.
3.9 MeV
D.
23 MeV
2010 NEET MCQ
AIPMT 2010 Prelims
The energy of a hydrogen atom in the ground state is $-$ 13.6 eV. The energy of a He+ ion in the first excited state will be
A.
$-$ 13.6 eV
B.
$-$ 27.2 eV
C.
$-$ 54.4 eV
D.
$-$ 6.8 eV
2010 NEET MCQ
AIPMT 2010 Prelims
The energy of a hydrogen atom in the ground state is $-$ 13.6 eV. The energy of a He+ ion in the first excited state will be
A.
$-$ 13.6 eV
B.
$-$ 27.2 eV
C.
$-$ 54.4 eV
D.
$-$ 6.8 eV
2009 NEET MCQ
AIPMT 2009
In a Rutherford scattering experiment when a projectile of charge z1 and mass M1 approaches 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 z1z2
B.
inversely proportional to z1
C.
directly proportional to mass M1
D.
directly proportional to M1 $ \times $ M2
2009 NEET MCQ
AIPMT 2009
The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an
A.
isomer of parent
B.
isotone of parent
C.
isotope of parent
D.
isobar of parent
2009 NEET MCQ
AIPMT 2009
In the nuclear decay given below

${}_Z^AX \to {}_{Z + 1}^AY \to {}_{Z - 1}^{A - 4}B{}^ * \to {}_{Z - 1}^{A - 4}B,$

the particles emitted in the sequence are
A.
$\gamma $, $\beta $, $\alpha $
B.
$\beta $, $\gamma $, $\alpha $
C.
$\alpha $, $\beta $, $\gamma $
D.
$\beta $, $\alpha $, $\gamma $
2009 NEET MCQ
AIPMT 2009
The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths, Maximum wavelength of emitted radiation corresponds to the transition between
A.
n = 3 to n = 1 states
B.
n = 2 to n = 1 states
C.
n = 4 to n = 3 states
D.
n = 3 to n = 2 states
2008 NEET MCQ
AIPMT 2008
Two radioactive materials X1 and X2 have decay constants $5\lambda $ and $\lambda $ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X1 to that X2 will be 1/e after a time
A.
1/4$\lambda $
B.
e/$\lambda $
C.
$\lambda $
D.
${1 \over 2}\lambda $
2008 NEET MCQ
AIPMT 2008
The ground state energy of hydrogen atom is $-$ 13.6 eV. When its electron is in the first excited state, its excitation energy is
A.
10.2 eV
B.
0
C.
3.4 eV
D.
6.8 eV
2008 NEET MCQ
AIPMT 2008
Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be
A.
${\left( 3 \right)^{1/3}}:1$
B.
1 : 1
C.
1 : 3
D.
3 : 1
2008 NEET MCQ
AIPMT 2008
If M(A; Z), Mp and Mn denote the masses of the nucleus ${}_Z^AX,$ proton and neutron respectively in units of u (1 u = 931.5 MeV/c2) and BE represents its bonding energy in MeV, then
A.
M(A, Z) = ZMp + (A $-$ Z)Mn $-$ BE
B.
M(A, Z) = ZMp + (A $-$ Z)Mn + BE/c2
C.
M(A, Z) = ZMp + (A $-$ Z)Mn $-$ BE/c2
D.
M(A, Z) = ZMp + (A $-$ Z)Mn + BE
2007 NEET MCQ
AIPMT 2007
In a radioactive decay process, the negatively charged emitted $\beta $-particles are
A.
the electrons produced as a result of the decay of neutrons inside the nucleus
B.
the electrons produced as a result of collisions between atoms
C.
the electrons orbitting around the nucleus
D.
the electrons present inside the nucleus
2007 NEET MCQ
AIPMT 2007
If the nucleus ${}_{13}^{27}Al$ has a nuclear radius of about 3.6 fm, them ${}_{32}^{125}Te$ would have its radius approximately as
A.
9.6 fm
B.
12.0 fm
C.
4.8 fm
D.
6.0 fm
2007 NEET MCQ
AIPMT 2007
In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential $V$ and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant, the ratio $\left( {{{ch\arg e\,\,on\,\,\,the\,\,ion\,\,} \over {mass\,\,of\,\,the\,\,ion}}} \right)$ will be proportional to
A.
1/R2
B.
R2
C.
R
D.
1/R
2007 NEET MCQ
AIPMT 2007
A nucleus ${}_Z^AX$ has mass represented by M(A, Z). If Mp and Mn denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then
A.
B.E. = [ZMp + (A $-$ Z)Mn $-$ M(A, Z)]c2
B.
B.E. = [ZMp + AMp $-$ M(A, Z)]c2
C.
B.E. = M(A, Z) $-$ ZMp $-$ (A $-$ Z)Mn
D.
B.E. = [M(A, Z) $-$ ZMp $-$ (A $-$ Z)Mn]c2
2007 NEET MCQ
AIPMT 2007
Two radioactive substances A and B have decay constants 5$\lambda $ and $\lambda $ respectively. At t = 0 they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be (1/e)2 after a time interval
A.
$4\lambda $
B.
$2\lambda $
C.
1/$2\lambda $
D.
1/$4\lambda $