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Optical smoke detectors work on the principle that smoke particles…

  • A
    are positively charged.
  • B
    are visible using internal optical lenses.
  • C
    are negatively charged.
  • D
    reflect and scatter light.

Refer to figure.
OPTICAL SMOKE DETECTORS
This detector type consists of a light source and a photocell positioned at an angle to each other. In normal conditions the transmitted light passes into a “light catcher” which prevents the reflection of light onto the receiver. In the event of fire, the smoke in the detector scatters the light onto the photocell and at a specific threshold value of light intensity the detector activates

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