In a subshell, if the number of radial nodes is two times the number of angular nodes, then the minimum possible value of the principal quantum number (n) is: 

[angular nodes are non-zero)

1. 1 2. 2
3. 3 4. 4

Subtopic:  Nodal Plane |
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The wavelength of a certain line in the Balmer series is observed to be 4341 Afor hydrogen atoms.
The electronic transition among the following may be:

1. 3 → 2
2. 4 → 1
3. 5 → 2
4. 5 → 3

Subtopic:  Bohr's Theory |
 58%
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The charge on the electron and proton are reduced to 23rd of their original values. Let the present value of the Rydberg constant of H-atom be R, then the new value of the Rydberg constant will be

1.  2R3
2.  4R9
3.  8R27
4.  16R81

Subtopic:  Bohr's Theory |
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The wavelength of the spectral line obtained in the spectrum of Li+2
when the transition takes place between levels whose sum is 4 and the difference is 2, will be:

1.  11.4 x 10-6 cm

2.  1.14 x 10-6cm

3.  0.114 x 10-6 cm

4.  1.14 x 10-8 cm

Subtopic:  Hydrogen Spectra |
 62%
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In the transition of an electron in an atom, its kinetic energy changes from y to y4. The change in potential energy will be -

1. \(\frac{-3}{8} y\)
2. \({{3}\over{2}}y\)
3. \({{3}\over{4}}y\)
4. \(-{{3}\over{4}}y\)

Subtopic:  Bohr's Theory |
 59%
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A photon with an initial frequency of \(10^{11}~\mathrm{Hz}\) scatters off an electron at rest. Its final frequency is \(0.9 \times10^{11}~\mathrm{Hz}.\) The speed of scattered electron is close to: 

1. \(3 \times10^{2}~\mathrm{ms}^{-1}\) 2. \(3.8 \times10^{3}~\mathrm{ms}^{-1}\)
3. \(2 \times10^{6}~\mathrm{ms}^{-1}\) 4. \(30~\mathrm{ms}^{-1}\)

Subtopic:  Photo Electric Effect |
 64%
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Photons of wavelength 4000  Ao are used to break l2 molecules. The percentage of energy converted to the kinetic energy of atoms will be :

(bond dissociation energy of the molecule is 246.5 kJ/mol)

1.  12%

2.  8%

3.  26%

4.  17%

Subtopic:  Electromagnetic Radiation |
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The number of unpaired electrons in 1s2 2s2 2p3 is -

1. 2

2. 0

3. 3

4. 1

Subtopic:  Pauli's Exclusion Principle & Hund's Rule |
 92%
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Be3+ion and a proton are accelerated by the same potential. The ratio of their de-Broglie wavelengths is

(assume mass of proton =  mass of neutron)

1. 1:2

2. 1:4

3. 1:1

4. 1:33

Subtopic:  Bohr's Theory |
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Assertion (A):  All d orbitals are tetra-lobed structures having two nodal planes.
Reason (R): Out of five, only four d-orbitals are degenerate orbitals.

1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false.

Subtopic:  Shell & Subshell |
 51%
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