Physics Test: Practice Questions On Compton Effect!

15 Questions | Total Attempts: 707

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Physics Test: Practice Questions On Compton Effect!

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Questions and Answers
  • 1. 
    The Compton shift Δλ is twice the Compton wavelength if the scattering angle is
    • A. 

      90°

    • B. 

      180°

    • C. 

      45°

    • D. 

  • 2. 
    According to Rayleigh-Jeans' radiation law, the emissive power of a blackbody over a wavelength range λ to λ+dλ is proportional to λⁿ. Then n is
    • A. 

      4

    • B. 

      1

    • C. 

      -2

    • D. 

      -4

  • 3. 
    The rest mass of a photon of frequency ν is
    • A. 

      Hν/c

    • B. 

      Hν/c²

    • C. 

      Zero

    • D. 

      Hν²/c

  • 4. 
    What is the speed of a particle whose mass is 3 times its rest mass?
    • A. 

      2c/3

    • B. 

      C/3

    • C. 

      √2c

    • D. 

      2√2c/3

  • 5. 
    In Compton scattering, if the angle of scattering varies from 0º to 180º, the electron's recoil angle varies from
    • A. 

      0º to 90º

    • B. 

      90º to 180º

    • C. 

      0º to 180º

    • D. 

      0º to 45º

  • 6. 
    The radiated intensity per unit time from a cavity kept at temperature 1000 Kelvin is 5.67x10ⁿ W/m². The value of n is
    • A. 

      8

    • B. 

      6

    • C. 

      4

    • D. 

      12

  • 7. 
    The de Broglie wavelength of an electron accelerated by a potential of 150 V is
    • A. 

      0.08 Å

    • B. 

      1 Å

    • C. 

      12.26 Å

    • D. 

      150 Å

  • 8. 
    The momentum of an electron (rest mass energy = 0.5 MeV) is 1 MeV/c. Its energy in MeV is
    • A. 

      1.5

    • B. 

      1.12

    • C. 

      1.22

    • D. 

      2.22

  • 9. 
    The de Broglie wavelength of a thermal neutron of mass m at temperature T is given by λ =
    • A. 

      H/√(3mkT)

    • B. 

      H/√(2mkT)

    • C. 

      √3h/(mkT)

    • D. 

      3h/√(2mkT)

  • 10. 
    In Davisson-Germer's experiment the highest peak was obtained at an angle θ = 50° with a voltage of 54 V. The de Broglie wavelength of electrons was
    • A. 

      1.67 Å

    • B. 

      0.167 Å

    • C. 

      0.227 Å

    • D. 

      2.27 Å

  • 11. 
    A proton accelerated through a potential difference of V has the same de Broglie wavelength as an α-particle subjected to a potential difference of
    • A. 

      4V

    • B. 

      V/4

    • C. 

      V/8

    • D. 

      8V

  • 12. 
    GaP, a semiconductor with an energy gap of 2.25 eV, is used to make LEDs. The wavelength of emitted light from pure GaP is
    • A. 

      705 nm

    • B. 

      515 nm

    • C. 

      630 nm

    • D. 

      555 nm

  • 13. 
    The peak wavelengths of radiation of a red-hot and a yellow-hot object are 630 nm and 570 nm respectively. If the red-hot object's temperature is 5000 K, the other's temperature is
    • A. 

      4000 K

    • B. 

      4500 K

    • C. 

      5000 K

    • D. 

      5500 K

  • 14. 
    In relation to Rayleigh-Jeans law, the ultraviolet catastrophe refers to the prediction
    • A. 

      E(ν) → 0 as ν → 0

    • B. 

      E(T) → ∞ as T → 0

    • C. 

      E(λ) → ∞ as λ → 0

    • D. 

      E(λ) → ∞ as λ → ∞

  • 15. 
    According to Planck, the average energy of cavity oscillators in the frequency range ν to ν+dν is given by
    • A. 

      Hν/(exp[hν/kT] - 1)

    • B. 

      Hν/(exp[hν/kT] + 1)

    • C. 

    • D. 

      Hν.exp[-hν/kT]

  • 16. 
    The energy of photons contained in visible light of wavelength 600 nm is
    • A. 

      2 eV

    • B. 

      2 keV

    • C. 

      2 MeV

    • D. 

      0.02 eV

  • 17. 
    If visible light is used in Compton scattering the Compton shift will be
    • A. 

      Negative

    • B. 

      Zero

    • C. 

      More positive than what is observed with X-rays

    • D. 

      Positive but not detectable in the visible window

  • 18. 
    The number of oscillation modes per unit volume for em standing waves of frequency ν in a blackbody cavity is proportional to
    • A. 

      ν³

    • B. 

      ν²

    • C. 

      ν

    • D. 

      Hν/(exp[hν/kT] - 1)

  • 19. 
    The Compton shift Δλ is half the Compton wavelength if the scattering angle is
    • A. 

      45°

    • B. 

      90°

    • C. 

      60°

    • D. 

      180°

  • 20. 
    Compton scattering is performed on blocks of carbon and silver. If I and I' are the intensities of the unmodified (λ) and Compton-shifted (λ') lines in the scattered X-rays, then
    • A. 

      I > I' for both carbon and silver

    • B. 

      I = I' for both carbon and silver

    • C. 

      I > I' for carbon, I < I' for silver

    • D. 

      I < I' for carbon, I > I' for silver

  • 21. 
    For cavity radiation of wavelength λ at absolute temperature T, Wien's radiation law corresponds to Planck's law when
    • A. 

      Photon's energy

    • B. 

      Photon's energy >> kT

    • C. 

      Photon's energy = kT

    • D. 

      Photon's energy has any finite value

  • 22. 
    If one measures the energy of a photon accurately the uncertainty in the measurement of frequency becomes
    • A. 

      Zero

    • B. 

    • C. 

      1

    • D. 

      ½

  • 23. 
    If the measured momentum of an electron is 3.20 x10ˉ²⁷ kg-m/s with an uncertainty of 1.6 x10ˉ²⁹ kg-m/s, what is the minimum uncertainty in the determination of its position?
    • A. 

      1.3 nanometer

    • B. 

      1.3 micrometer

    • C. 

      3.3 nanometer

    • D. 

      3.3 micrometer

  • 24. 
    The Compton wavelength for electron is
    • A. 

      0.24 Å

    • B. 

      0.024 Å

    • C. 

      2.4 Å

    • D. 

      0.0024 Å

  • 25. 
    The disagreement between Rayleigh-Jeans' predictions and experimental results for blackbody radiation spectrum is known as
    • A. 

      Infrared signature

    • B. 

      Twin paradox

    • C. 

      Ultraviolet catastrophe

    • D. 

      Gibb's paradox