The wavelength \(\lambda_{e}\) of an electron and \(\lambda_{p}\) of a photon of the same energy E are related as:
1.
2.
3.
4.
An \(\alpha -\) particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of \(0.25 \mathrm{~Wb} / \mathrm{m}^2\). The de-Broglie wavelength associated with the particle will be:
1. | \(1~\mathring {\text{A}}\) | 2. | \(0.1~\mathring {\text{A}}\) |
3. | \(10~\mathring {\text{A}}\) | 4. | \(0.01~\mathring {\text{A}}\) |
If the momentum of an electron is changed by p, then the de-Broglie wavelength associated with it changes by 0.5%. What is the initial momentum of the electron?
1. 200p
2. 400p
3.
4. 100p
The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface having a work function of 5.01 eV when ultraviolet light of 200 nm falls on it is:
1. | 2.4 V | 2. | - 1.2 V |
3. | - 2.4 V | 4. | 1.2 V |
When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I what is the number of emitted electrons and their maximum kinetic energy?
1. | N and 2T | 2. | 2N and T |
3. | 2N and 2T | 4. | N and T |
A helium-neon laser produces monochromatic light of a wavelength of 667 nm. The power emitted is 9 mW. The average number of photons arriving per second on average at a target irradiated by this beam is:
1.
2.
3.
4.
A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of . What will be the velocity of the particle? (mass of electrons = 9 . 1 × 10- 31 kg )
1. | \(2.7 \times 10^{-18} \mathrm{~ms}^{-1}\) |
2. | \(9 \times 10^{-2} \mathrm{~ms}^{-1}\) |
3. | \(3 \times 10^{-31} \mathrm{~ms}^{-1}\) |
4. | \(2.7 \times 10^{-21} \mathrm{~ms}^{-1}\) |
Waves are associated with matter only:
1. | When it is stationary. |
2. | When it is in motion with the velocity of light only. |
3. | When it is in motion with any velocity. |
4. | None of the above. |
A particle which has zero rest mass and non-zero energy and momentum must travel with a speed:
1. | Equal to c, the speed of light in vacuum. |
2. | Greater than c. |
3. | Less than c. |
4. | Tending to infinity. |
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