Lasers
Physics ⇒ Modern Physics
Lasers starts at 11 and continues till grade 12.
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Describe the difference between a three-level and a four-level laser system.
Describe the role of the optical resonator (cavity) in a laser.
Explain the term 'population inversion' in the context of lasers.
Explain why a laser beam does not spread out as much as ordinary light.
Explain why lasers are used in optical fiber communication.
Explain why population inversion is necessary for laser action.
State one advantage of using lasers in medical surgery.
State one major difference between spontaneous emission and stimulated emission.
Which of the following best describes the light emitted by a laser?
(1) Incoherent and polychromatic
(2) Coherent and monochromatic
(3) Incoherent and monochromatic
(4) Coherent and polychromatic
Which of the following is a gas laser?
(1) Ruby laser
(2) Nd:YAG laser
(3) He-Ne laser
(4) Semiconductor laser
Which of the following is a solid-state laser?
(1) Ruby laser
(2) He-Ne laser
(3) CO₂ laser
(4) Dye laser
Which of the following is NOT a characteristic of laser light?
(1) High intensity
(2) High divergence
(3) Monochromaticity
(4) Coherence
Fill in the blank: The first working laser was constructed by _______ in 1960.
The acronym 'LASER' stands for _______.
The process by which an excited atom is induced to emit a photon and return to a lower energy state is called _______.
The process of supplying energy to the active medium in a laser is called _______.
True or False: All lasers require an external pumping source to achieve population inversion.
True or False: In a laser, the population of atoms in the excited state must be greater than in the ground state for lasing to occur.
True or False: Semiconductor lasers are commonly used in CD and DVD players.
True or False: The output of a laser is always visible to the human eye.
