1. Laser beams are produced by:
(A) Thermal radiation
(B) Stimulated emission of photons
(C) Scattering of light
(D) Reflection from mirrors
2. The process of producing laser light starts with:
(A) Cooling of atoms
(B) Excitation of atoms to higher energy levels
(C) Absorption of sound waves
(D) Reflection of light
3. What is the active medium in a laser?
(A) The power supply
(B) The lens used to focus the beam
(C) The material where atoms are excited to emit photons
(D) The external mirrors
4. Pumping in lasers refers to:
(A) Emitting light
(B) Supplying energy to the active medium
(C) Reflecting photons
(D) Cooling the laser
5. Which of the following is used as a pumping source?
(A) Magnetic field
(B) Electrical discharge
(C) Sound waves
(D) Mechanical vibration
6. Population inversion means:
(A) Equal number of atoms in excited and ground states
(B) More atoms in excited state than in ground state
(C) All atoms in ground state
(D) No atoms excited
7. Population inversion is necessary for:
(A) Reflection
(B) Thermal radiation
(C) Laser action
(D) Diffusion of light
8. Which mirrors are used in a laser setup?
(A) Lenses
(B) Only convex mirrors
(C) Only concave mirrors
(D) Two mirrors at both ends of the active medium
9. One mirror in a laser setup is fully reflective while the other is:
(A) Fully reflective
(B) Partially reflective to allow beam emission
(C) Transparent
(D) Convex only
10. The light emitted by laser is:
(A) Diffused
(B) Incoherent
(C) Coherent
(D) Scattered
11. The process in which an excited atom emits a photon of the same energy as an incoming photon is called:
(A) Stimulated emission
(B) Spontaneous emission
(C) Absorption
(D) Reflection
12. Which of the following is a necessary condition for laser production?
(A) Cooling of medium
(B) Population inversion
(C) Diffuse light
(D) Polychromatic light
13. Spontaneous emission is:
(A) Emission of photon without external influence
(B) Emission of photon due to external photon
(C) Absorption of photon
(D) Reflection of light
14. Stimulated emission leads to:
(A) Absorption of light
(B) Amplification of light
(C) Diffusion of light
(D) Reflection
15. A laser cavity is also called:
(A) Beam splitter
(B) Light box
(C) Optical resonator
(D) Lasing chamber
16. Which of the following determines the wavelength of laser light?
(A) Pumping energy only
(B) Mirror shape
(C) Type of active medium
(D) Beam diameter
17. Ruby laser uses which type of pumping?
(A) Magnetic pumping
(B) Electrical pumping
(C) Optical pumping
(D) Thermal pumping
18. Helium-Neon laser uses which pumping?
(A) Electrical discharge
(B) Optical pumping
(C) Thermal pumping
(D) Magnetic pumping
19. Laser light is amplified inside the cavity by:
(A) Absorption
(B) Single reflection
(C) Diffusion
(D) Multiple reflections between mirrors
20. Which part of laser allows emission of a narrow, intense beam?
(A) Partially reflective mirror
(B) Fully reflective mirror
(C) Active medium
(D) Lens only
21. Which phenomenon is exploited in laser production?
(A) Diffraction
(B) Spontaneous reflection
(C) Polarization only
(D) Stimulated emission
22. The beam emitted from a laser is:
(A) Polychromatic
(B) Monochromatic and directional
(C) Scattered
(D) Diffused
23. Nd:YAG laser produces:
(A) Red light
(B) Infrared light
(C) Blue light
(D) Green light
24. Which type of mirror reflects all photons back into the medium?
(A) Fully reflective mirror
(B) Partially reflective mirror
(C) Concave lens
(D) Convex mirror
25. The main steps in laser production are:
(A) Pumping → Population inversion → Stimulated emission → Amplification
(B) Diffusion → Absorption → Reflection
(C) Scattering → Reflection → Diffusion
(D) Emission → Reflection → Transmission
26. Laser light has which of the following properties due to production process?
(A) Incoherent
(B) Polychromatic
(C) Monochromatic, coherent, directional
(D) Diffused
27. Which medium is used in CO₂ laser?
(A) Ruby crystal
(B) Carbon dioxide gas
(C) Semiconductor diode
(D) Dye solution
28. Optical pumping involves:
(A) Electrical excitation
(B) Using light to excite atoms
(C) Magnetic field excitation
(D) Thermal excitation
29. The purpose of the mirrors in laser production is:
(A) Color the light
(B) Reduce light intensity
(C) Scatter light
(D) Amplify light by multiple reflections
30. The emitted laser beam is highly:
(A) Scattered
(B) Diffused and weak
(C) Polychromatic
(D) Intense and focused