Embibe Experts Solutions for Chapter: Semiconductor Devices, Exercise 1: KCET (UG) 2019

A positive hole in a semiconductor is

The density of an electron-hole pair in pure germanium is $3\times {10}^{16} m^{-3}$ at room temperature. On doping with aluminium, the hole density increases to $4.5\times {10}^{22 }{\mathrm{m}}^{-3}$. Now the electron density (in ${\mathrm{m}}^{-3}$ ) in doped germanium will be

Three photodiodes $D_1,D_2$ and $D_3$ are made of semiconductors having band gaps of $2.5\mathrm{eV}$, $2\mathrm{eV}$ and $3\mathrm{eV}$ respectively. Which one will be able to detect light of wavelength $\lambda =6000 \mathrm{\AA }?$

Identify the incorrect statement:

The dc common-emitter current gain of a $\text{N-P-N}$ transistor is $50 .$ The potential difference applied across the collector and emitter of a transistor used in $CE$ configuration is, $V_{CE}=2\text{V}$. If the collector resistance, $R_C=4\text{ K}\Omega$, the base current $\left(I_B\right)$ and the collector current $\left(I_C\right)$ will be:

In a $CE$ amplifier, the input ac signal to be amplified is applied across

The circuit given represents which of the logic operations?

If $A=1$ and $B=0$, then in terms of Boolean algebra, $A+B=$