Semi conductor devices practice · Mixed difficulty

With the fall in temperature, the electric conductivity of intrinsic semiconductors

A working transistor with its three legs marked $P,Q$ and $R$ is tested using a multimeter. No conduction is found between $P$ and $Q$. By connecting the common (negative) terminal of the multimeter to $R$ and the other (positive) terminal to $P$ or $Q$, some resistance is seen on the multimeter. Which of the following is true for the transistor?

The Boolean equation $\mathrm{x}=[(\mathrm{A}+\overline{\mathrm{B}}) \cdot(\mathrm{B}+\mathrm{C})] \cdot \mathrm{B}$ can be simplified to

Bonding in a germanium crystal (semi-conductor) is

An AND gate can be prepared by repetitive use of
(a) NOT gate $\,\,\,\,\,\,\,\,$ (b) OR gate $\,\,\,\,\,\,\,\,$ (c) NAND gate $\,\,\,\,\,\,\,\,$ (d) NOR gate

For which of the following the resistance decreases on increasing the temperature

The value of $\left( {\frac{1}{\beta } - \frac{1}{\alpha }} \right)$ is equal to :- ($\alpha$ and $\beta$ are current gain in CB & CE configuration).

Integrated chip (IC) is an electronic device that contains

Statement-I: The dominant mechanism for motion of charge carriers in forward and reverse biased silicon $\mathrm{P}-\mathrm{N}$ junction are drift in both forward and reverse bias.

Statement-II: In reverse biasing, no current flow through the junction.

If a LED forward biased, then

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $6200 \, \mathop {\text{A}}\limits^ \circ,$ is incident on it. The band gap in (eV) for the semiconductor is

In $CE$ mode, the input characteristics of a transistor is the variation of

Statement I: If forward current changes by $1.5 \mathrm{~mA}$ when forward voltage in semiconductor diode is changed from $0.5 \mathrm{~V}$ to $2 \mathrm{~V}$, the forward resistance of diode will be $1 \Omega$.

Statement II: The forward resistance is given by $R_f=\frac{\Delta V_f}{\Delta I_f}$

A $p - n\;$ photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

Assertion: The resistivity of a semi-conductor increases with temperture.

Reason: the atoms of semi conductor vibrate with large amplitude at higher temperture thereby increasing its resistivity.

A piece of copper and another of germanium are cooled from room temperature (300 K) to 280 K, the resistance of

In Boolean algebra, $\overline {\bar A \cdot \bar B}$ is equal to

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity.

Reason R: For a p-n junction diode, at applied voltage $V$ the current in the forward bias is more than the current in the reverse bias for $\left|V_{z}\right|> \pm V \geq$ $\left|V_{0}\right|$ where $V_{0}$ is the threshold voltage and $V_{z}$ is the breakdown voltage.

In the light of the above statements, choose the correct answer from the options given below

If ${D_e}$ , ${D_b}$ and ${D_c}$ are the doping levels of emitter, base and collector respectively of a transistor, then

The saturation current in a diode valve is governed by

The mobility of free electrons is greater than that of free holes because they

Two diodes have resistance 20 $\mathrm{\Omega }$ and is centretapped with rms secondary voltage from centre tap to each end of secondary 50 V. If external resistance is 980 $\mathrm{\Omega }$. What is mean load?

The temperature coefficient of resistance of a conductor is

Assertion : Photodiode & photovoltaic cell are based on the same principle.

Reason : Both use same method of operations to work.

Would there be any advantage to adding $n$-type or $p$-type impurities to copper

In a P-type semiconductor, the acceptor impurity produces an energy level

A common emitter amplifier is designed with $NPN$ transistor $\left( {\alpha = 0.99} \right)$. The input impedance is $1\;K\mathrm{\Omega }$ and load is $10\;K\mathrm{\Omega }$. The voltage gain will be

In Colpitt oscillator the feedback network consists of

The output of a NAND gate is 0

A zener diode has a contact potential of 1 V in the absence of biasing. It undergoes Zener breakdown for an electric field of ${10^6}$ V-${\mathrm{m}^{ - 1}}$ at the depletion region of $p$-$n$ junction. If the width of the depletion region is 2.5 $\mu$m, what should be the reverse biased potential for the Zener breakdown to occur?