Quantum Physics MCQ

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 (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

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 (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

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

  • 90°
  • 180°
  • 45°

Answer: 180°

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