Electrons of mass m with de- Broglie wavelength λ fall on the target in an X-ray tube. The cut-off wavelength (λo) of the emitted X-ray is:
1.
2.
3.
4.
If an electron in a hydrogen atom jumps from the \(3^{\text{rd}}\) orbit to the \(2^{\text{nd}}\) orbit, it emits a photon of wavelength \(\lambda\). When it jumps from the \(4^{\text{th}}\) orbit to the \(3^{\text{rd}}\) orbit, the corresponding wavelength of the photon will be:
1. | \(\frac{16}{25}\lambda\) | 2. | \(\frac{9}{16}\lambda\) |
3. | \(\frac{20}{7}\lambda\) | 4. | \(\frac{20}{13}\lambda\) |
The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom is:
1. \(1:1\)
2. \(1:-1\)
3. \(2:-1\)
4. \(1:-2\)
The ratio of the longest wavelengths corresponding to the Lyman and Balmer series in the hydrogen spectrum is:
1. | \(\frac{3}{23}\) | 2. | \(\frac{7}{29}\) |
3. | \(\frac{9}{31}\) | 4. | \(\frac{5}{27}\) |
Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be \(3.57~\text{V}\). The threshold frequency of the material is:
1. \(4\times10^{15}~\text{Hz}\)
2. \(5\times10^{15}~\text{Hz}\)
3. \(1.6\times10^{15}~\text{Hz}\)
4. \(2.5\times10^{15}~\text{Hz}\)
If the nucleus has a nuclear radius of about 3.6 fermis, then would have its radius approximately as:
1. 6.0 Fermi
2. 9.6 Fermi
3. 12.0 Fermi
4. 4.8 Fermi
In a discharge tube ionization of enclosed gas is produced due to collisions between:
1. positive ions and neutral atoms/molecules
2. negative electrons and neutral atoms/molecules
3. photons and neutral atoms/molecules
4. neutral gas atoms/molecules
The radius of Germanium (Ge) nuclide is measured to be twice the radius of . The number of nucleons in Ge is:
1. 73
2. 74
3. 75
4. 72