A _______ is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.

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RRB ALP Electronics Mechanic 23 Jan 2019 Official Paper (Shift 3)
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  1. Diode
  2. Laser
  3. Resistor
  4. Tristor

Answer (Detailed Solution Below)

Option 2 : Laser
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Concept:

Laser

  • A laser is a device for producing simulated emissions of electromagnetic action.
  • Laser stands for light amplification by stimulated emission of (electromagnetic) radiation.
  • Laser is used in laser printers, barcode scanners, DNA sequencing instruments, laser surgery,  skin treatments, cutting and welding materials, measuring range and speed, etc.
  • Luminescence is the spontaneous emission of light by a substance not resulting from heat; or "cold light".

Additional Information

  • Dispersion: It is defined as the spreading of white light into its full spectrum of colors (in order violet, indigo, blue, green, yellow, orange, and red).
  • Radiation that spreads out in different directions from a radiation beam when the beam interacts with a substance is defined as Scattered radiation.
  • Stimulated emission, in laser action, is the release of energy from an excited atom by artificial means.
    • Stimulated emission occurs when a photon, with an energy level equal to the energy gap, interacts with the electron.
  • Spontaneous emission takes place without interaction with other photons, and the direction and phase are random while Stimulated emission takes place when the excited electron interacts with another photon.
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