## Quantum Physics MCQ

Quantum Physics MCQ, Multiple Choice Questions on Quantum Physics, Objective Questions on Quantum Physics, MCQ on Quantum Physics, Engineering MCQ, Engineering Physics MCQ

### Multiple Choice Questions

Q.1. Matter waves are:

- Elastic waves
- Electromagnetic waves
- Show diffraction
- Transverse wave

**Answer: **Show diffraction

Q.2. The wavelength *λ* associated with a particle of mass *m* moving with velocity *v* is given by

- \lambda =\frac{h}{m\nu }
- \lambda =\frac{m}{h\nu }
- \lambda =\frac{m\nu }{h }
- \lambda =\frac{h\nu }{m}

**Answer: **\lambda =\frac{h}{m\nu }

Q.3. The de-Broglie hypothesis is associated with:

- wave nature of electrons only
- wave nature of α-particle only
- wave nature of radiations
- wave nature of all material particles

**Answer: **wave nature of all material particles

Q.4. De-Broglie wavelength of a material particle having a kinetic energy, E is proportional to

- \sqrt{E}
- \frac{1}{\sqrt{E}}
- E
- \frac{1}{E}

**Answer: **\frac{1}{\sqrt{E}}

Q.5. The equation of motion of matter wave was derived by:

- Heisenberg
- Bohr
- de-Broglie
- Schrodinger

**Answer: **Schrodinger

Q.6. If the momentum of a particle is increased to four times, then the de-Broglie wavelength will become:

- two times
- four times
- half times
- one-fourth times

**Answer:** one-fourth times

Q.7. de- Broglie wavelength of an electron which has been accelerated from rest through a potential difference of 100 V is

- 12.27 Å
- 1.227 Å
- 15 Å
- 1.5 Å

**Answer: **1.227 Å

Q.8. According to wave mechanics, a material particle is associated with :

- a single wave
- a wave packet
- progressive wave
- light wave

**Answer: **a wave packet

Q.9. The wavelength of the matter waves is independent of:

- mass
- velocity
- charge
- momentum

**Answer: **charge

Q.10. Assuming the velocity to be same, which particle is having longest wavelength

- an electron
- a proton
- a neutron
- an α-particle

**Answer: **an electron

Q.11. The rest mass of a photon is

- zero
- 1.67 x 10
^{-31}kg - 1.9 x 10
^{-27}kg - infinity

**Answer: **zero

Q.12. The group velocity of matter waves is:

- less than particle velocity
- equal to particle velocity
- shows diffraction
- transverse wave

**Answer: **equal to particle velocity

Q.13. A photon and an electron have the same wavelength then:

- photon has greater momentum
- electron has greater momentum
- both have the same momentum
- none of the above

**Answer: **both have the same momentum

Q.14. Matter waves were first experimentally observed by:

- de-Broglie
- Schrodinger
- Davisson and Germer
- Bohr

**Answer: **Davisson and Germer

Q.15. Davisson and Germer experiment relates to:

- interference
- polarization
- electron diffraction
- phosphorence

**Answer: **electron diffraction

Q.16. Dual nature of matter was predicted by:

- Schrodinger
- Louis de-Broglie
- G.P. Thomson
- Werner Heisenberg

**Answer: **Louis de-Broglie

Q.17. The phase velocity (v_{p}) and group velocity (v_{g}) of a de Broglie wave in free space are related as:

- v_{p}=v_{g}
- v_{p}v_{g}=c^{2}
- v_{p}=\frac{v_{g}}{2}
- v_{p}=\frac{c^{2}}{2v_{g}}

**Answer: **v_{p}v_{g}=c^{2}

Q.18. Uncertainty principle states that the error in measurement is due to:

- dual nature of particles
- due to small size of particles
- due to large size of particles
- due to error in measuring instrument

**Answer: **dual nature of particles

Q.19. The product of uncertainties between position and momentum is given by:

- \Delta x\Delta p=\lambda
- \Delta x\Delta p=h
- \Delta x\Delta p=nh
- \Delta x\Delta p=m\nu

**Answer: **\Delta x\Delta p=h

Q.20. If the uncertainty in the location of a particle is equal to de-Broglie wavelength, the uncertainty in its velocity will be:

- equal to its velocity
- half of its velocity
- twice its velocity
- four times its velocity

**Answer: **equal to its velocity

Q.21. For a non-relativistic free particle, the phase velocity (v_{p}) and group velocity (v_{g}) is related as:

- v_{p}=v_{g}
- v_{p}=\frac{v_{g}}{2}
- v_{p}=2v_{g}
- v_{g}=\frac{v_{p}^{2}}{2}

**Answer: **v_{p}=\frac{v_{g}}{2}

Q.22. Which of the following can act as both a particle and as a wave?

- photon
- electron
- neutron
- all of these

**Answer: **all of these

Q.23. A proton with an energy of 2.05 MeV has a de-Broglie wavelength of

- 3 x 10
^{-19}m - 3 x 10
^{-7}m - 2 x 10
^{-14}m - 1.5 x 10
^{-14}m

**Answer: **2 x 10^{-14} m

Q.24. An electron is in a box 2 nm across. What will be the lowest energy for the electron?

- 0.01 eV
- 0.08375 eV
- 0.2 eV
- 1.5 eV

**Answer: **0.08375 eV

Q.25. The velocity of X-rays in vacuum is:

- less than velocity of light
- equal to the velocity of light
- greater than velocity of light
- none of these

**Answer: **equal to the velocity of light

Q.26. X-rays were discovered by:

- Moseley
- Duane and Hunt
- W.L. Bragg
- W. Roentgen

**Answer: **W. Roentgen

Q.27. In Compton effect the electron that takes part is

- free
- bound
- may be free or bound
- emitted from nucleus by decay of neutrons

**Answer: **emitted from nucleus by decay of neutrons

Q.28. Compton shift is given by:

- \frac{h}{m_{e}c^{2}}(1-\cos \phi )
- \frac{h}{m_{e}c}(1-\sin \phi )
- \frac{h}{m_{e}c}(1-\cos \phi )
- \frac{h}{m_{e}c^{2}}(1+\cos \phi )

**Answer: **\frac{h}{m_{e}c}(1-\cos \phi )

Q.29. Compton shift (Δλ) is maximum when angle of scattering of photon (ϕ) is:

- \phi =\pi
- \phi =0
- \phi =\frac{\pi}{2}
- \phi =\frac{\pi}{4}

**Answer: **\phi =\pi

Q.30. Compton effect is associated with:

- visible light
- X-rays
- β-rays
- positive rays

**Answer: **X-rays

Q.31. Compton shift (Δλ) depends on:

- incident wavelength
- angle of scattering
- target material
- energy of incident light

**Answer: **angle of scattering

Q.32. In which direction the recoil electron in compton scattering has the maximum energy

- 0°
- 90°
- 180°
- 45°

**Answer: **180°