THE ATOMIC SPECTRA
1. What is the atomic spectra?
a) The emission of light by atoms
b) The absorption of light by atoms
c) The arrangement of atoms in a crystal lattice
d) The movement of atoms in a chemical reaction
2. The spectrum of a hydrogen atom consists of:
a) Discrete lines
b) A continuous band
c) A combination of discrete lines and a continuous band
d) No spectrum is observed for a hydrogen atom
3. The Bohr model for the hydrogen atom explains:
a) The discrete energy levels of the atom
b) The continuous energy distribution of the atom
c) The arrangement of protons and neutrons in the nucleus
d) The emission of X-rays by the atom
4. Excitation of an atom refers to:
a) The transition of an electron to a higher energy level
b) The transition of an electron to a lower energy level
c) The removal of an electron from the atom
d) The addition of a proton to the atom
5. Ionization potential is defined as:
a) The energy required to excite an electron to a higher energy level
b) The energy required to remove an electron from an atom
c) The energy released when an electron is added to an atom
d) The energy released when an atom gains a proton
6. X-ray spectra consist of:
a) Discrete lines
b) A continuous band
c) Both discrete lines and a continuous band
d) No spectrum is observed for X-rays
7. X-ray bremsstrahlung refers to:
a) Emission of X-rays due to electron transitions within the atom
b) Absorption of X-rays by atoms
c) Scattering of X-rays by a crystal lattice
d) Deceleration of fast electrons, resulting in the emission of X-rays
8. Characteristic X-ray spectra arise from:
a) Electron transitions within the atom
b) Nuclear reactions occurring in the atom
c) Reflection of X-rays from a crystal lattice
d) The addition of protons to the nucleus
9. What is the principle behind lasers?
a) Stimulated emission of radiation
b) Absorption of radiation by atoms
c) Scattering of radiation by a crystal lattice
d) Random emission of radiation by atoms
10. The laser operates based on:
a) The population inversion of energy levels
b) The absorption of radiation by atoms
c) The reflection of radiation from a crystal lattice
d) The random emission of radiation by atoms
11. Which of the following materials is commonly used in a ruby laser?
a) Aluminum
b) Copper
c) Ruby crystal
d) Glass
12. In the operation of a ruby laser, the pumping mechanism provides:
a) Energy to excite electrons to higher energy levels
b) Energy to ionize the atoms
c) Energy to cool down the laser medium
d) Energy to remove electrons from the laser medium
13. What are some applications of lasers?
a) Laser surgery
b) Optical communications
c) Laser printing
d) All of the above
14. Laser surgery is widely used for:
a) Eye correction surgeries
b) Cosmetic procedures
c) Cancer treatment
d) Joint replacement surgeries
15. The laser beam in laser printing is used for:
a) Writing text on paper
b) Detecting errors in printed documents
c) Transferring ink onto paper
d) Scanning images for reproduction
16. What is the primary advantage of lasers in optical communications?
a) High transmission speeds
b) Long transmission distances
c) Low cost
d) Compatibility with all types of signals
17. Which of the following correctly describes the atomic spectra?
a) Emission and absorption of specific wavelengths of light by atoms
b) Emission of a continuous band of light by atoms
c) Scattering of light by atoms
d) Reflection of light by atoms
18. The spectrum of a hydrogen atom consists of:
a) Discrete lines corresponding to different energy levels
b) A continuous band of light
c) A combination of discrete lines and a continuous band
d) No spectrum is observed for a hydrogen atom
19. The Bohr model for the hydrogen atom explains:
a) The discrete energy levels of the atom
b) The continuous energy distribution of the atom
c) The arrangement of protons and neutrons in the nucleus
d) The emission of X-rays by the atom
20. Excitation of an atom refers to:
a) The transition of an electron to a higher energy level
b) The transition of an electron to a lower energy level
c) The removal of an electron from the atom
d) The addition of a proton to the atom
21. Ionization potential is defined as:
a) The energy required to excite an electron to a higher energy level
b) The energy required to remove an electron from an atom
c) The energy released when an electron is added to an atom
d) The energy released when an atom gains a proton
22. X-ray spectra consist of:
a) Discrete lines corresponding to different energy levels
b) A continuous band of X-rays
c) A combination of discrete lines and a continuous band
d) No spectrum is observed for X-rays
23. X-ray bremsstrahlung refers to:
a) Emission of X-rays due to electron transitions within the atom
b) Absorption of X-rays by atoms
c) Scattering of X-rays by a crystal lattice
d) Deceleration of fast electrons, resulting in the emission of X-rays
24. Characteristic X-ray spectra arise from:
a) Electron transitions within the atom
b) Nuclear reactions occurring in the atom
c) Reflection of X-rays from a crystal lattice
d) The addition of protons to the nucleus
25. The principle behind lasers is:
a) Stimulated emission of radiation
b) Absorption of radiation by atoms
c) Scattering of radiation by a crystal lattice
d) Random emission of radiation by atoms
26. Which of the following materials is commonly used as the gain medium in a helium-neon (He-Ne) laser?
a) Ruby crystal
b) Carbon dioxide gas
c) Helium gas
d) Neodymium-doped crystal
27. The energy levels in a laser gain medium are populated by:
a) Absorption of photons
b) Emission of photons
c) Collisional processes
d) Ionization of atoms
28. The term "laser" stands for:
a) Light Amplification by Stimulated Emission of Radiation
b) Low-Energy Atomic Spectra Emission Radiator
c) Luminescent Absorption and Scattering of Electromagnetic Radiation
d) Linear Amplitude Spectrum and Energy Redistribution
29. The output of a laser is typically:
a) Monochromatic and coherent
b) Polychromatic and incoherent
c) Monochromatic and incoherent
d) Polychromatic and coherent
30. The population inversion required for laser operation is achieved by:
a) Increasing the temperature of the gain medium
b) Introducing a three-level system
c) Applying a strong magnetic field
d) Pumping energy into the gain medium
31. Which of the following materials is commonly used as the gain medium in a semiconductor laser?
a) Silicon crystal
b) Gallium arsenide
c) Nitrogen gas
d) Aluminum foil
32. The process of spontaneous emission in a laser:
a) Results in the release of photons without external stimulation
b) Amplifies the incident light
c) Produces coherent light
d) Requires a population inversion
33. The term "lasing threshold" refers to:
a) The minimum energy required to achieve population inversion
b) The maximum energy level reached during laser operation
c) The minimum energy required to excite electrons in the gain medium
d) The maximum energy loss due to optical losses in the laser cavity
34. Which of the following factors determines the wavelength of laser emission?
a) Energy levels of the gain medium
b) Pumping mechanism
c) Type of laser cavity
d) Operating temperature of the laser
35. In a gas laser, the gain medium is typically excited by:
a) Electrical discharge
b) Optical pumping
c) Chemical reaction
d) Magnetic field
36. The laser medium in a carbon dioxide (CO2) laser is excited by:
a) Electrical discharge
b) Optical pumping
c) Chemical reaction
d) Magnetic field
37. The process of stimulated emission in a laser involves:
a) Absorption of a photon by an excited electron
b) Spontaneous emission of a photon by an excited electron
c) Emission of a photon by an excited electron due to external stimulation
d) De-excitation of an electron to a lower energy level
38. Which of the following laser types is known for its extremely short pulse duration?
a) Continuous-wave (CW) laser
b) Q-switched laser
c) Mode-locked laser
d) Diode laser
39. The concept of "population inversion" in a laser refers to:
a) An equal distribution of electrons among different energy levels
b) A higher number of electrons in the lower energy levels
c) A higher number of electrons in the upper energy levels
d) The absence of electrons in the energy levels
40. The laser beam in a CD/DVD player is used for:
a) Reading data from the disc
b) Writing data onto the disc
c) Reflecting light for signal detection
d) Controlling the disc rotation speed
41. What is the energy of a photon with a wavelength of 600 nm?
a) 3.31 eV
b) 2.07 eV
c) 1.24 eV
d) 0.83 eV
42. The frequency of an X-ray photon is 3.0 × 10^18 Hz. What is its energy in electron volts (eV)?
a) 6.63 eV
b) 4.14 eV
c) 2.48 eV
d) 1.65 eV
43. If the energy difference between two energy levels of an atom is 2.0 eV, what is the wavelength of the photon emitted during the transition?
a) 620 nm
b) 310 nm
c) 155 nm
d) 103 nm
44. The ionization potential of an atom is 10 eV. What is the minimum frequency of light required to ionize the atom?
a) 1.24 × 10^14 Hz
b) 2.48 × 10^14 Hz
c) 4.14 × 10^14 Hz
d) 6.63 × 10^14 Hz
45. The energy levels of a hydrogen atom are given by the formula E = -13.6/n^2 eV, where n is the principal quantum number. What is the energy difference between the n = 3 and n = 4 energy levels?
a) 0.85 eV
b) 1.51 eV
c) 2.55 eV
d) 3.40 eV
46. A laser emits light with a wavelength of 632.8 nm. What is the frequency of the emitted light?
a) 4.74 × 10^14 Hz
b) 4.74 × 10^14 s^-1
c) 4.74 × 10^14 cycles/s
d) 4.74 × 10^14 rad/s
47. The gain medium of a laser has an energy gap of 2 eV. What is the minimum wavelength of light required to achieve population inversion in the gain medium?
a) 620 nm
b) 310 nm
c) 155 nm
d) 103 nm
48. The speed of light in a vacuum is approximately 3.0 × 10^8 m/s. What is the wavelength of a laser beam with a frequency of 5.0 × 10^14 Hz?
a) 6.0 × 10^-7 m
b) 4.8 × 10^-7 m
c) 3.0 × 10^-7 m
d) 2.0 × 10^-7 m
49. A laser emits light with a power output of 10 mW. If the wavelength of the laser is 532 nm, how many photons are emitted by the laser per second?
a) 3.56 × 10^19 photons/s
b) 1.79 × 10^19 photons/s
c) 8.95 × 10^18 photons/s
d) 4.48 × 10^18 photons/s
50. The intensity of a laser beam is 2.5 × 10^4 W/m^2. If the beam has a cross-sectional area of 0.02 m^2, what is the total power of the laser beam?
a) 500 W
b) 250 W
c) 50 W
d) 60 W
ANSWER KEY:
1. a) The emission of light by atoms
2. a) Discrete lines
3. a) The discrete energy levels of the atom
4. a) The transition of an electron to a higher energy level
5. b) The energy required to remove an electron from an atom
6. c) Both discrete lines and a continuous band
7. d) Deceleration of fast electrons, resulting in the emission of X-rays
8. a) Electron transitions within the atom
9. a) Stimulated emission of radiation
10. a) The population inversion of energy levels
11. c) Ruby crystal
12. a) Energy to excite electrons to higher energy levels
13. d) All of the above
14. c) Cancer treatment
15. c) Transferring ink onto paper
16. a) High transmission speeds
17. a) Emission and absorption of specific wavelengths of light by atoms
18. a) Discrete lines corresponding to different energy levels
19. a) The discrete energy levels of the atom
20. a) The transition of an electron to a higher energy level
21. b) The energy required to remove an electron from an atom
22. c) A combination of discrete lines and a continuous band
23. d) Deceleration of fast electrons, resulting in the emission of X-rays
24. a) Electron transitions within the atom
25. a) Stimulated emission of radiation
26. c) Helium gas
27. b) Emission of photons
28. a) Light Amplification by Stimulated Emission of Radiation
29. a) Monochromatic and coherent
30. d) Pumping energy into the gain medium
31. b) Gallium arsenide
32. a) Results in the release of photons without external stimulation
33. a) The minimum energy required to achieve population inversion
34. a) Energy levels of the gain medium
35. a) Electrical discharge
36. a) Electrical discharge
37. c) Emission of a photon by an excited electron due to external stimulation
38. c) Mode-locked laser
39. c) A higher number of electrons in the upper energy levels
40. a) Reading data from the disc
41. a) 3.31 eV
42. b) 4.14 eV
43. c) 155 nm
44. d) 6.63 × 10^14 Hz
45. b) 1.51 eV
46. a) 4.74 × 10^14 Hz
47. d) 103 nm
48. c) 3.0 × 10^-7 m
49. a) 3.56 × 10^19 photons/s
50. c) 50 W
