AP Physics 1 Questions on the Photoelectric Effect: Challenge Yourself

💡 Quick Study Guide

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• The Photoelectric Effect is the emission of electrons when light hits a material.
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• Einstein explained it by proposing that light consists of photons, each with energy $E = hf$, where $h$ is Planck's constant ($6.626 x 10^{-34} Js$) and $f$ is the frequency.
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• The work function ($\phi$) is the minimum energy required to remove an electron from a solid.
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• The kinetic energy ($KE$) of the emitted electron is given by $KE = hf - \phi$.
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• If $hf < \phi$, no electrons are emitted, regardless of the intensity of the light.
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• The stopping potential ($V_s$) is the voltage required to stop the emitted electrons, and $KE_{max} = eV_s$, where $e$ is the elementary charge ($1.602 x 10^{-19} C$).

🧪 Practice Quiz

1. Which of the following statements is TRUE regarding the photoelectric effect?
   1. A) The number of emitted electrons depends only on the frequency of the incident light.
   2. B) The kinetic energy of emitted electrons depends only on the intensity of the incident light.
   3. C) The number of emitted electrons depends on the intensity of the incident light.
   4. D) No electrons are emitted if the frequency of the incident light is above a certain threshold.
2. What happens to the kinetic energy of photoelectrons if the frequency of the incident light is increased?
   1. A) It decreases.
   2. B) It remains the same.
   3. C) It increases.
   4. D) It becomes zero.
3. The work function of a metal is 2.0 eV. What is the minimum frequency of light required to emit photoelectrons?
   1. A) $4.84 \times 10^{14}$ Hz
   2. B) $4.84 \times 10^{13}$ Hz
   3. C) $4.84 \times 10^{15}$ Hz
   4. D) $4.84 \times 10^{12}$ Hz
4. What is the effect on the photocurrent if the intensity of the incident light is increased (assuming the frequency is above the threshold)?
   1. A) It decreases.
   2. B) It remains the same.
   3. C) It increases.
   4. D) It becomes zero.
5. If the stopping potential for a certain metal is 1.5 V, what is the maximum kinetic energy of the photoelectrons (in eV)?
   1. A) 0.75 eV
   2. B) 1.0 eV
   3. C) 1.5 eV
   4. D) 3.0 eV
6. Which of the following best explains why the photoelectric effect supports the particle theory of light?
   1. A) It shows that light can diffract around obstacles.
   2. B) It demonstrates that light can interfere with itself.
   3. C) It reveals that light consists of photons with specific energy.
   4. D) It proves that light travels in waves.
7. Light of wavelength 300 nm is incident on a metal surface with a work function of 1.5 eV. What is the maximum kinetic energy of the emitted photoelectrons (in eV)?
   1. A) 2.64 eV
   2. B) 5.64 eV
   3. C) 1.14 eV
   4. D) 4.14 eV