# Quantum Physics MCQ Posted by

## 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

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 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

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

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

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

• a single wave
• a wave packet
• progressive wave
• light wave

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

• mass
• velocity
• charge
• momentum

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

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

Q.11. The rest mass of a photon is

• zero
• 1.67 x 10-31 kg
• 1.9 x 10-27 kg
• infinity

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

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

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

Q.15. Davisson and Germer experiment relates to:

• interference
• polarization
• electron diffraction
• phosphorence

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

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

Q.17. The phase velocity (vp) and group velocity (vg) 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

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

Q.21. For a non-relativistic free particle, the phase velocity (vp) and group velocity (vg) 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

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

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

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

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

Q.31. Compton shift (Δλ) depends on:

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