Semi conductor devices practice · Mixed difficulty

A LED (light emitting diode) in its proper Operation is

Assertion: A P-N photodiode is made from a semiconductor for which $\mathrm{Eg}=2.8 \mathrm{eV}$. This photodiode will not detect the wavelength of $6000 \mathrm{~nm}$.

Reason: A PN photodiode detects wavelength I if $\frac{h c}{\lambda} > E_g$

In a transistor the collector current is always less than the emitter current because

A light emitting diode (LED) is fabricated using Ga. As semiconducting material whose band gap is $1.42 \mathrm{~eV}$. The wavelength of light emitted from the LED is:

Number of secondary electrons emitted per number of primary electrons depends on

In half wave rectification, if the input frequency is 60 Hz, then the output frequency would be:

In a transistor the base is

Which of the following materials in non crystalline

Consider the following statements

(i) An intrinsic semiconductor will behave as insulator at T = 0 K

(ii) Doping pure silicon with trivalent impurities gives p-type semiconductors

(iii) The majority carriers in n-type semiconductors are electrons

(iv) Solar cell works when it is in forward bias

The correct statements(s) is/are

Consider the following statements I and II and
identify the correct answer from the given options.

Statement-I: A zener diode should be connected
in reverse bias for proper functioning.

Statement-II: The potential barrier of a silicon
p-n junction lies between 2 V and 5 V.

Choose the correct answer from the options given
below.

Name of a $p$-$n$ junction, which can be used as the regulator, is

In silicon when phosphorus is doped ……. is formed

If the slope of the characteristics curve of a vacuum tube diode corresponding to some point is ${10^{ - 3}}\mathrm{mA}{\mathrm{V}^{ - 1}}$, then the plate resistance of diode and its nature are respectively

The emission of electrons from the host atoms due
to the high electric field is known as

Assertion: A transistor is a voltage operating device.
Reason: Base current is greater than the collector current.

Which of the following has negative temperature coefficient of resistance

In an intrinsic semiconductor, the Fermi level is

The potential in depletion layer is due to

Statement I: When base region has larger width, the collector current increases.

Statement II: Electron-hole combination in base results in increases of base current.

An electron-hole pair is formed when light of maximum wavelength 6000 $\mathop A\limits^ \circ$ is incident on the semiconductor. What is the band gap energy of the semiconductor?

($h = 6.62\; \times {10^{ - 34}}$ J-s)

For a common emitter configuration, if $\alpha$ and $\beta$ have their usual meanings, the incorrect relationship between $\alpha$ and $\beta$ is

While a collector to emitter voltage is constant in a transistor, the collector current changes by $8.2\;mA$ when the emitter current changes by $8.3\;mA$. The value of forward current ratio ${h_{fe}}$ is

The current gain of a transistor in common base mode is 0.995. the current gain of the same transistor in common emitter mode is

For a junction diode the ratio of forward current $\left( {{I_F}} \right)$ and reverse current $\left( {{I_r}} \right)$ is

[${I_e} =$electronic charge, $V =$voltage applied across junction, $k =$ Boltzmann constant, $T =$temperature in kelvin]

Zener breakdown in a semi-conductor diode occurs when

Which of the following statements is not correct when a junction diode is in forward bias?

If no external voltage is applied across $P$-$N$ junction, there would be

Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is more appropriate?

A p-n photodiode is made of a material with a band gap of 1.0 eV. The maximum wavelength of radiation that can be absorbed by the material is nearly

Which of the following is an amorphous substance?