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. | \(30~\mathrm{ms}^{-1}\) |
In the transition of an electron in an atom, its kinetic energy changes from y to . The change in potential energy will be -
1. \(\frac{-3}{8} y\)
2. \({{3}\over{2}}y\)
3. \({{3}\over{4}}y\)
4. \(-{{3}\over{4}}y\)
The wavelength of the spectral line obtained in the spectrum of
when the transition takes place between levels whose sum is 4 and the difference is 2, will be:
1. 11.4 x cm
2. 1.14 x cm
3. 0.114 x cm
4. 1.14 x cm
The charge on the electron and proton are reduced to 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
The wavelength of a certain line in the Balmer series is observed to be 4341 Ao for hydrogen atoms.
The electronic transition among the following may be:
1. 3 → 2
2. 4 → 1
3. 5 → 2
4. 5 → 3
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 |
Photons of wavelength 4000 are used to break 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%
The number of unpaired electrons in 1s2 2s2 2p3 is -
1. 2
2. 0
3. 3
4. 1
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:
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. |