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Photoelectric Effect EM radiation can – under certain circumstances – knock electrons out

Photoelectric Effect EM radiation can – under certain circumstances – knock electrons out of molecules and surfaces. Imagine a clean calcium surface under vacuum, and assume that you can somehow measure if electrons are emitted from the surface.

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Photoelectric Effect EM radiation can – under certain circumstances – knock electrons out

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  1. Photoelectric Effect EM radiation can – under certain circumstances – knock electrons out of molecules and surfaces.Imagine a clean calcium surface under vacuum, and assume that you can somehow measure if electrons are emitted from the surface. Green light strikes the surface, and no electrons are emitted. Could electrons possibly be emitted if you (A) doubled the light intensity? (B) used red light instead of green? (C) used UV light instead of green? (D) none of the above.

  2. Photoelectric Effect EM radiation can – under certain circumstances – knock electrons out of molecules and surfaces.Imagine a clean calcium surface under vacuum, and assume that you can somehow measure if electrons are emitted from the surface. Green light strikes the surface, and no electrons are emitted. Could electrons possibly be emitted if you (A) doubled the light intensity? (B) used red light instead of green? (C) used UV light instead of green? (D) none of the above.

  3. Photoelectric Effect Assume that electrons are emitted from the metal surface with some kinetic energy Ekin. We now apply a positive voltage U to the metal, holding the detector plate at zero voltage. Which of the following statements is correct? (A) Positive voltage accelerates the electrons towards the detector plate. We will measure a current independent of the voltage as long as it is positive.(B) The voltage has to be greater than Ekin in order to measure a current. Otherwise, the kinetic energy of the electrons is too great, the electrons will leave the setup and there will be no current.(C) As long as the voltage U < Ekin/e, we will measure a current. Otherwise, the positive voltage creates a force that “pulls” the electrons back into the metal surface before they can reach the detector.

  4. Photoelectric Effect Assume that electrons are emitted from the metal surface with some kinetic energy Ekin. We now apply a positive voltage U to the metal, holding the detector plate at zero voltage. Which of the following statements is correct? (A) Positive voltage accelerates the electrons towards the detector plate. We will measure a current independent of the voltage as long as it is positive.(B) The voltage has to be greater than Ekin in order to measure a current. Otherwise, the kinetic energy of the electrons is too great, the electrons will leave the setup and there will be no current.(C) As long as the voltage U < Ekin/e, we will measure a current. Otherwise, the positive voltage creates a force that “pulls” the electrons back into the metal surface before they can reach the detector.

  5. Light has the properties of ... (A)… waves (B)… particles (C)… both (D)... neither

  6. Light has the properties of ... (A)… waves (B)… particles (C)… both (D)... neither

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