Light Emitting Diode (L.E.D), Photodiode, Solar Cell PYQs: JEE Mains Physics

Showing 1–10 of 10 questions

1. 1. Consider the following statements:
   A. The junction area of solar cell is made very narrow compared to a photo diode.
   B. Solar cells are not connected with any external bias.
   C. LED is made of lightly doped p-n junction.
   D. Increase of forward current results in continuous increase of LED light intensity.
   E. LEDs have to be connected in forward bias for emission of light.
   Choose the correct answer from the options given below: 2025 Easy
2. 2. A light emitting diode \((LED)\) is fabricated using GaAs semiconducting material whose band gap is \(1.42 \mathrm{eV}\). The wavelength of light emitted from the \(LED\) is _______. 2024 Hard
3. 3. A potential divider circuit is connected with a DC source of \(20 \mathrm{~V}\), a light emitting diode of glow in voltage \(1.8 \mathrm{~V}\) and a zener diode of breakdown voltage of \(3.2 \mathrm{~V}\). The length (PR) of the resistive wire is \(20 \mathrm{~cm}\). The minimum length of \(P Q\) to just glow the LED is _______ cm.
   2024 Hard
4. 4. Conductivity of a photodiode starts changing only if the wavelength of incident light is less than \(660 \mathrm{~nm}\). The band gap of photodiode is found to be \(\left(\frac{x}{8}\right) \mathrm{eV}\). The value of \(x\) is _______. (Given, \(\mathrm{h}=6.6 \times 10^{-34} \mathrm{Js}, \mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\) ) 2024 Hard
5. 5. Which of the following statement is not correct in the case of light emitting diodes? \(A.\) It is a heavily doped p-n junction. \(B.\) It emits light only when it is forward biased. \(C.\) It emits light only when it is reverse biased. \(D.\) The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used. Choose the correct answer from the options given below : 2023 Medium
6. 6. The energy band gap of semiconducting material to produce violet (wavelength \(=4000 \,A^{\circ}\) ) LED is \(.......eV\). (Round off to the nearest integer). 2022 Easy
7. 7. The photodiode is used to detect the optiocal signals. These diodes are preferably operated in reverse biased mode because. 2022 Medium
8. 8. \(LED\) is constructed from \(Ga-As-P\) semiconducting material. The energy gap of this \(LED\) is \(1.9\, eV\). Calculate the wavelength of light emitted and its colour. \(\left[ h =6.63 \times 10^{-34} \;Js \right.\) and \(\left. c =3 \times 10^{8}\; ms ^{-1}\right]\) 2021 Medium
9. 9. With increasing biasing voltage of a photodiode, the photocurrent magnitude 2020 Medium
10. 10. Identify the semiconductor devices whose characteristics are given below, in the order \((a),(b),(c),(d) \) 
    2016 Medium

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