Semiconductors & Electronic Devices JEE Main PYQs, 2020 to 2025

Consider a n-type semiconductor in which $\mathrm{n}_{\mathrm{e}}$ and $\mathrm{n}_{\mathrm{h}}$ are number of electrons and holes, respectively.

(A) Holes are minority carriers

(B) The dopant is a pentavalent atom

(C) $\mathrm{n}_{\mathrm{e}} \mathrm{n}_{\mathrm{h}} \neq \mathrm{n}_i^2$

(where $\mathrm{n}_i$ is number of electrons or holes in semiconductor when it is intrinsic form)

(D) $\mathrm{n}_{\mathrm{e}} \mathrm{n}_{\mathrm{h}} \geqslant \mathrm{n}_i^2$

(E) The holes are not generated due to the donors

Choose the correct answer from the options given below :

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 :

In an n-p-n common emitter (CE) transistor the collector current changes from 5 $\mathrm{mA}$ to $16 \mathrm{~mA}$ for the change in base current from $100~ \mu \mathrm{A}$ and $200 ~\mu \mathrm{A}$, respectively. The current gain of transistor is __________.

Choose the correct statement about Zener diode :

The energy band gap of semiconducting material to produce violet (wavelength = 4000$\mathop A\limits^o$ ) LED is ______________ $\mathrm{eV}$. (Round off to the nearest integer).