Q. No.
If the de-Broglie wavelengths for a proton and an alpha-particle are equal, then the ratio of their velocities will be:
1. \(4:1\)
2. \(2:1\)
3. \(1:2\)
4. \(1:4\)
1. \(4:1\)
2. \(2:1\)
3. \(1:2\)
4. \(1:4\)
How much energy should be added to an electron to reduce its de-Broglie wavelength from \(10^{-10}\) m to \(0.5\times10^{-10}\) m?
1. Four times the initial energy.
2. Thrice the initial energy.
3. Equal to the initial energy.
4. Twice the initial energy.
If the following particles are moving at the same velocity, then which among them will have the maximum de-Broglie wavelength?
1. Neutron
2. Proton
3. \(β
-\)particle
4. \(α
-\)particle
| 1. | \(\frac{1}{8}\) | 2. | \(\frac{3}{8}\) |
| 3. | \(\frac{5}{8}\) | 4. | \(\frac{7}{8}\) |
1. \(\sqrt{2}:1\)
2. \(2:1\)
3. \(2\sqrt{2}:1\)
4. \(\frac{1}{2\sqrt{2}}:1\)
| 1. | \(1.5 \times 10^{-23}~\text{kg-m/s}\) |
| 2. | \(6.6 \times 10^{-24}~\text{kg-m/s}\) |
| 3. | \(6.6 \times 10^{-44}~\text{kg-m/s}\) |
| 4. | \(2.2 \times 10^{-52}~\text{kg-m/s}\) |
1. \(6.6\times 10^{-19}~\text{J}\)
2. \(6.6\times 10^{-12}~\text{J}\)
3. \(6.6\times 10^{-49}~\text{J}\)
4. \(6.6\times 10^{-41}~\text{J}\)
The number of photo-electrons emitted per second from a metal surface increases when:
| 1. | The energy of incident photons increases. | 2. | The frequency of incident light increases. |
| 3. | The wavelength of the incident light increases. | 4. | The intensity of the incident light increases. |
| 1. | \(1.4~\text{eV}\) | 2. | \(1.7~\text{eV}\) |
| 3. | \(5.4~\text{eV}\) | 4. | \(6.8~\text{eV}\) |
The spectrum of radiation \(1.0\times 10^{14}\) Hz is in the infrared region.
The energy of one photon of this in joules will be:
1. \(6.62\times 10^{-48}\)
2. \(6.62\times 10^{-20}\)
3. \(\frac{6.62}{3}\times 10^{-28}\)
4. \(3\times 6.62\times 10^{-28}\)
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