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MHT CET Medical202622 April 2026Evening ShiftPhysicsSemiconductorsActual

Which of the following LED emits red and yellow light?

Options

  1. AGa - As - P
  2. BGa - P
  3. CGa - As
  4. DAs - P

Correct answer

A. Ga - As - P

Step-by-step solution

The semiconductor used for fabrication of visible LEDs must have a band gap of at least 1.8 eV . Gallium Arsenide Phosphide ( GaAs _ 1-x P _x ) is used for making LEDs of different colours such as red, yellow, and orange. For example, GaAs _ 0.6 P _ 0.4 ( E_g 1.9 eV ) is used for red LEDs. Gallium Arsenide ( GaAs ) has a band gap of 1.4 eV and is used for infrared LEDs. Gallium Phosphide ( GaP ) is typically used for green LEDs. Thus, Ga - As - P is the material that emits red and yellow light. Answer: Ga - As - P

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