1. Identify the phenomena that serve as evidence for the quantum nature of light. Select the correct answer. A-1, 2, 3
A-1, 2, 3; B-3 and 4; C-4
2. Which of the following expressions most accurately defines the concept of the photoelectric effect? Specify the correct answer.
A. The emission of electrons from a substance due to its heating.
B. The ejection of electrons from a substance under the influence of light.
C. The increase in electrical conductivity of a substance under the influence of light.
3. Who formulated the laws of the photoelectric effect? Choose the correct answer.
A-1; B-2; C-3
4. What parameters affect the maximum kinetic energy of electrons released from a metal by light?
A- intensity of light; B- frequency; C- work function; D- frequency and work function.
5. Determine from the graph in which case the intensity of light incident on the metal is greater?
A- 1; B- 2; C-3.
6. Which of the following expressions precisely defines the concept of work function? Specify the correct answer.
A. The energy required to detach an electron from an atom.
B. The kinetic energy of a free electron in a substance.
C. The energy required for a free electron to exit a substance.
7. Which of the following expressions allows you to calculate the energy of a photon of radiation? Specify the correct answers.
A. Avogadro’s number + kinetic energy
B. hv — kinetic energy
C. Avogadro’s number + mv^2/2
8. Under what condition is the photoelectric effect possible? Specify the correct answers.
A. hv > work function
B. hv = work function
C. hv < work function
9. Which of the following statements (for a given electrode) is true?
A) The work function depends on the wavelength of incident radiation.
B) The "threshold" voltage depends on the work function.
C) Increasing the wavelength of incident radiation leads to an increase in the speed of ejected photoelectrons.
D) The maximum speed of ejected photoelectrons depends only on the work function.
E) Increasing the frequency of incident radiation leads to an increase in the speed of photoelectrons.
10. How will the work function change when the wavelength of incident radiation on the cathode increases fourfold?
A) It will increase fourfold.
B) It will decrease fourfold.
C) It will increase twofold.
D) It will decrease twofold.
E) It will not change.
11. According to which of the following formulas can you calculate the momentum of a photon? (E-energy of the photon; c-speed of light)
A) Ec
B) Ec^2
C) c/E
D) c^2/E
E) E/cλ
12. Which of the following graphs corresponds to the dependence of the mass of a photon on its wavelength?
A) [Graph 1]
B) [Graph 2]
C) [Graph 3]
D) [Graph 4]
E) [Graph 5]
13. The energy of a photon is proportional to:
1) wavelength; 2) emission time; 3) photon speed; 4) oscillation frequency;
14. The energy of photons decreases by a factor of 2 when the wavelength of light is halved.
1) It decreases by a factor of 2; 2) It increases by a factor of 2; 3) It decreases by a factor of 4; 4) It increases by a factor of 4.
15. What is the maximum kinetic energy of electrons ejected from a metal when exposed to photons with an energy of 8*10^-19 J, if the work function is 2*10^-19 J? Specify the correct answers.
A. 10*10^-19 J; B. 6*10^-19 J; C. 5*10^-19 J
16. Identify the substance for which the photoelectric effect is possible when exposed to photons with an energy of 4.8*10^-19 J. Specify all correct answers.
A. Platinum (work function=8.5*10^-19 J); B. Silver (work function=6.9*10^-19 J); C. Lithium (work function=3.8*10^-19 J).
17. What is the maximum kinetic energy of electrons ejected from barium oxide when illuminated with light of a frequency of 1 PHz?
18. The red threshold of the photoelectric effect for a metal is 6.2*10^-5 cm. Find the value of the stopping voltage for photoelectrons when the metal is illuminated with light with a wavelength of 330 nm.
19. Determine the maximum speed of an electron ejected from cesium when illuminated with light with a wavelength of 400 nm.
20. A photocathode coated with calcium (work function = 4.42*10^-19 J) is illuminated with light with a wavelength of 300 nm. The electrons ejected from the cathode enter a uniform magnetic field with an induction of 8.3*10^-4 T perpendicular to the lines of induction of this field. What is the maximum radius of the circle along which the electrons move?
Quantum nature of light is evidenced by several phenomena.
1. Photoelectric Effect: When light is incident on a material, it can eject electrons from the material’s surface. The fact that the intensity, but not the frequency, determines the kinetic energy of ejected electrons supports the idea that light is quantized in packets called photons.
2. Compton Scattering: When X-rays or high-energy photons collide with electrons, they change their direction and lose some of their energy. This phenomenon demonstrates that the energy of photons is proportional to their frequency, providing further evidence for quantization.
3. Wave-Particle Duality: The phenomenon of interference and diffraction observed in the double-slit experiment suggests that light behaves both as particles (photons) and waves. This duality is a hallmark of quantum nature.
Definition of the Photoelectric Effect:
The correct answer is B. The photoelectric effect is the ejection of electrons from a substance under the influence of light. When photons with sufficient energy strike a metal surface, they transfer energy to electrons, enabling them to overcome the binding forces of the material.
Formulator of the Laws of the Photoelectric Effect:
The correct answer is A. Albert Einstein formulated the laws of the photoelectric effect, for which he was awarded the Nobel Prize in Physics in 1921.
Задание:
Explain the concept of wave-particle duality and provide an example from everyday life where this phenomenon is observed.