d. Forward bias current and light intensity 27. When used in forward biased, it emits characteristic, almost monochromatic light. It emits light while conducting. When forward bias is applied, the electron and holes at the junction recombine and energy released is emitted in the form of light. Explanation. ... Because the green LED in circuit B is forward biased, and reverse biased in circuit A. ? Question Number. d) Both (a) and (c) above Answer-A 2. 1. NEET Physics Notes Modern Physics-Electronic Devices-Light Emitting Diode (LED) Light Emitting Diode (LED) It is a specially designed diode made of GaAsP, GaP etc. An LED has a high forward bias voltage drop but is easily damaged when reverse biased. 2. The cross-sectional view of a commercial LED is shown in figure (b). The conventional current in a PN junction diode flows: (a) From positive to negative (b) From negative to positive (c) In the direction opposite to the electron flow. ... Because the red LED in circuit B is forward biased, and it is reverse biased in circuit A. The circuit has … The cut in voltage (or knee voltage) of a silicon diode is (a) 0.2V (b) 0.7V (c) 0.8 V (d) 1.0V Answer-B 3. When testing the forward bias of a diode with a multimeter. Since, electrical energy is converted into light energy, this process is also called electroluminescence. ... c. emitter-base junction is forward biased and collector-base junction is forward biased d. none of them . 36. It also conducts when forward biased and does not conduct when reverse biased. A special semiconductor material is used in Light Emitting Diodes (LED). A light emitting diode (LED) emits light only when . P-N junction photodiode has to be a. Correct Answer is. Reverse biased b. To protect it from AC. When P-N junction diode is in forward biased condition, the flow of current is mainly due to _____ ... • A LED (light emitting diode) is also a two terminal device. a. a. In reverse biased, it works like a normal diode. c) DH structures d) To increase current spreading d) Negligible (b) 1.33 A The LEDs made with GaAs emit light in the, Enter the code above here : Fringing reefs with a chain of 21 islands from Rameswaram in the north to Thoothukudi (Tuticorin) in the south. When the diode is forward biased, electrons from the semiconductors conduction band recombine with holes from the valence band releasing sufficient energy to produce photons which emit a monochromatic (single colour) of light. The emitter of a transistor is generally doped the heaviest because it . A LED is a special type of device that emits light when current passes through it. Forward biased c. Switched on d. Switched off 28. We know that a single p-n junction diode connected to an a-c source acts as a half wave rectifier [Forward biased in one half cycle and reverse biased in the other half cycle]. 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