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question_answer1)
Which of the following atoms and ions are isoelectronic i.e. have the same number of electrons with the neon atom [NCERT 1978]
A)
\[{{F}^{-}}\] done
clear
B)
Oxygen atom done
clear
C)
\[Mg\] done
clear
D)
\[{{N}^{-}}\] done
clear
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question_answer2)
Atoms consists of protons, neutrons and electrons. If the mass of neutrons and electrons were made half and two times respectively to their actual masses, then the atomic mass of \[_{6}{{C}^{12}}\] [NCERT 1982]
A)
Will remain approximately the same done
clear
B)
Will become approximately two times done
clear
C)
Will remain approximately half done
clear
D)
Will be reduced by 25% done
clear
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question_answer3)
The increasing order (lowest first) for the values of \[e/m\] (charge/mass) for [IIT 1984]
A)
\[e,\,p,\,n,\,\alpha \] done
clear
B)
\[n,\,p,\,e,\,\alpha \] done
clear
C)
\[n,\,p,\,\alpha ,e\] done
clear
D)
\[n,\,\alpha ,\,p,\,e\] done
clear
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question_answer4)
The electronic configuration of a dipositive metal \[{{M}^{2+}}\] is 2, 8, 14 and its atomic weight is 56 a.m.u. The number of neutrons in its nuclei would be [MNR 1984, 89; Kerala PMT 1999]
A)
30 done
clear
B)
32 done
clear
C)
34 done
clear
D)
42 done
clear
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question_answer5)
The ratio of the energy of a photon of \[2000{AA}\] wavelength radiation to that of \[4000{AA}\] radiation is [IIT 1986; DCE 2000; JIPMER 2000]
A)
1/4 done
clear
B)
4 done
clear
C)
1/2 done
clear
D)
2 done
clear
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question_answer6)
Discovery of the nucleus of an atom was due to the experiment carried out by [CPMT 1983; MP PET 1983]
A)
Bohr done
clear
B)
Mosley done
clear
C)
Rutherford done
clear
D)
Thomson done
clear
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question_answer7)
In a Bohr's model of atom when an electron jumps from \[n=1\] to \[n=3\], how much energy will be emitted or absorbed [CBSE PMT 1996]
A)
\[2.15\times {{10}^{-11}}erg\] done
clear
B)
\[0.1911\times {{10}^{-10}}erg\] done
clear
C)
\[2.389\times {{10}^{-12}}erg\] done
clear
D)
\[0.239\times {{10}^{-10}}erg\] done
clear
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question_answer8)
The nucleus of an atom can be assumed to be spherical. The radius of the nucleus of mass number \[A\] is given by \[1.25\times {{10}^{-13}}\times {{A}^{1/3}}cm\] Radius of atom is one \[{AA}\]. If the mass number is 64, then the fraction of the atomic volume that is occupied by the nucleus is [NCERT 1983]
A)
\[1.0\times {{10}^{-3}}\] done
clear
B)
\[5.0\times {{10}^{-5}}\] done
clear
C)
\[2.5\times {{10}^{-2}}\] done
clear
D)
\[1.25\times {{10}^{-13}}\] done
clear
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question_answer9)
The energy of an electron in the first Bohr orbit of \[H\]atom is \[-13.6eV\]. The possible energy value(s) of the excited state(s) for electrons in Bohr orbits to hydrogen is(are) [IIT 1998; Orissa JEE 2005]
A)
\[-3.4eV\] done
clear
B)
\[-4.2eV\] done
clear
C)
\[-6.8eV\] done
clear
D)
\[+6.8eV\] done
clear
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question_answer10)
The energy of the electron in the first orbit of \[H{{e}^{+}}\] is \[-871.6\times {{10}^{-20}}J\]. The energy of the electron in the first orbit of hydrogen would be [Roorkee Qualifying 1998]
A)
\[-871.6\times {{10}^{-20}}J\] done
clear
B)
\[-435.8\times {{10}^{-20}}J\] done
clear
C)
\[-217.9\times {{10}^{-20}}J\] done
clear
D)
\[-108.9\times {{10}^{-20}}J\] done
clear
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question_answer11)
The total number of valence electrons in \[4.2\,gm\] of \[N_{3}^{-}\] ion is (\[{{N}_{A}}\] is the Avogadro's number) [CBSE PMT 1994]
A)
\[1.6{{N}_{A}}\] done
clear
B)
\[3.2{{N}_{A}}\] done
clear
C)
\[2.1{{N}_{A}}\] done
clear
D)
\[4.2{{N}_{A}}\] done
clear
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question_answer12)
The Bohr orbit radius for the hydrogen atom \[(n=1)\] is approximately \[0.530{AA}\]. The radius for the first excited state \[(n=2)\] orbit is [CBSE PMT 1998; BHU 1999]
A)
\[0.13{AA}\] done
clear
B)
\[1.06{AA}\] done
clear
C)
\[4.77{AA}\] done
clear
D)
\[2.12{AA}\] done
clear
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question_answer13)
The frequency of a wave of light is \[12\times {{10}^{14}}{{s}^{-1}}.\] The wave number associated with this light is [Pb. PMT 1999]
A)
\[5\times {{10}^{-7}}m\] done
clear
B)
\[4\times {{10}^{-8}}c{{m}^{-1}}\] done
clear
C)
\[2\times {{10}^{-7}}{{m}^{-1}}\] done
clear
D)
\[4\times {{10}^{4}}c{{m}^{-1}}\] done
clear
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question_answer14)
The series limit for Balmer series of H-spectra is [AMU (Engg.) 1999]
A)
3800 done
clear
B)
4200 done
clear
C)
3646 done
clear
D)
4000 done
clear
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question_answer15)
The ionization energy of hydrogen atom is \[-13.6\,eV.\] The energy required to excite the electron in a hydrogen atom from the ground state to the first excited state is (Avogadro?s constant = 6.022 × 1023) [BHU 1999]
A)
\[1.69\times {{10}^{-20}}J\] done
clear
B)
\[1.69\times {{10}^{-23}}J\] done
clear
C)
\[1.69\times {{10}^{23}}J\] done
clear
D)
\[1.69\times {{10}^{25}}J\] done
clear
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question_answer16)
The energy required to dislodge electron from excited isolated H-atom, \[I{{E}_{1}}=13.6\,\,eV\] is [DCE 2000]
A)
\[=\,13.6\,eV\] done
clear
B)
\[>\,13.6\,eV\] done
clear
C)
\[<13.6\]and\[>3.4\,eV\] done
clear
D)
\[\le \,3.4\,eV\] done
clear
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question_answer17)
The number of nodal planes in a \[{{p}_{x}}\] is [IIT Screening 2000]
A)
One done
clear
B)
Two done
clear
C)
Three done
clear
D)
Zero done
clear
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question_answer18)
The third line in Balmer series corresponds to an electronic transition between which Bohr?s orbits in hydrogen [MP PMT 2001]
A)
5 ® 3 done
clear
B)
5 ® 2 done
clear
C)
4 ® 3 done
clear
D)
4 ® 2 done
clear
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question_answer19)
Which of the following has maximum number of unpaired electron (atomic number of Fe 26) [MP PMT 2001]
A)
Fe done
clear
B)
Fe (II) done
clear
C)
Fe (III) done
clear
D)
Fe (IV) done
clear
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question_answer20)
The frequency of one of the lines in Paschen series of hydrogen atom is \[2.340\times {{10}^{11}}Hz.\] The quantum number \[{{n}_{2}}\] which produces this transition is [DPMT 2001]
A)
6 done
clear
B)
5 done
clear
C)
4 done
clear
D)
3 done
clear
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question_answer21)
Which of the following electron transition in a hydrogen atom will require the largest amount of energy [UPSEAT 1999, 2000, 01]
A)
From \[n=1\] to \[n=2\] done
clear
B)
From \[n=2\] to \[n=3\] done
clear
C)
From \[n=\infty \] to \[n=1\] done
clear
D)
From \[n=3\] to \[n=5\] done
clear
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question_answer22)
In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen [AIEEE 2003]
A)
3 ® 2 done
clear
B)
5 ® 2 done
clear
C)
4 ® 1 done
clear
D)
2 ® 5 done
clear
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question_answer23)
The value of Planck?s constant is \[6.63\times {{10}^{-34}}Js.\] The velocity of light is \[3.0\times {{10}^{8}}\,m{{s}^{-1}}\]. Which value is closest to the wavelength in nanometres of a quantum of light with frequency of \[8\times {{10}^{15}}{{s}^{-1}}\] [CBSE PMT 2003]
A)
\[3\times {{10}^{7}}\] done
clear
B)
\[2\times {{10}^{-25}}\] done
clear
C)
\[5\times {{10}^{-18}}\] done
clear
D)
\[4\times {{10}^{1}}\] done
clear
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question_answer24)
As electron moves away from the nucleus, its potential energy [UPSEAT 2003]
A)
Increases done
clear
B)
Decreases done
clear
C)
Remains constant done
clear
D)
None of these done
clear
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