Semi conductor devices practice · Mixed difficulty

A metallic surface with work function of $2\;eV$, on heating to a temperature of 800 $K$ gives an emission current of $1\;mA$. If another metallic surface having the same surface area, same emission constant but work function $4\;eV$ is heated to a temperature of $1600\;K$, then the emission current will be

If we add impurity to a metal those atoms also deflect electrons. Therefore

A photodetector used to detect the wavelength of 1700 nm, has energy gap of about

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

Assertion A: Photodiodes are preferably operated in reverse bias condition for light intensity measurement.

Reason R: The current in the forward bias is more than the current in the reverse bias for a $p-n$ junction diode.

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

For the transistor circuit as shown. If $\beta \mathrm{ } = \mathrm{ }100$, voltage drop between emitter and base is 0.7 V then value of ${V_{CE}}$ will be

In $N$-type semiconductors, majority charge carriers are

Boolean expression for $OR$ gate is

Statement I: In a common-emitter transistor amplifier the input current is much less than output current.

Statement II: The common-emitter transistor amplifier has very high input impedance.

The relation between dynamic plate resistance $\left( {{r_p}} \right)$ of a vacuum diode and plate current in the space charge limited region, is

The slope of plate characteristic of a vacuum tube diode for certain operating point on the curve is ${10^{ - 3}}\frac{{mA}}{V}$. The plate resistance of the diode and its nature respectively

Pure $Si$ at $500\;K$ has equal number of electron $\left( {{n_e}} \right)$ and hole $\left( {{n_h}} \right)$ concentrations of $1.5 \times {10^{16}}{m^{ - 3}}$. Doping by indium increases ${n_h}$ to $4.5 \times {10^{22}}{m^{ - 3}}$. The doped semiconductor is of

To write the decimal number 37 in binary, how many binary digits are required

In a triode amplifier, the value of maximum gain is equal to

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, $h=6.6 \times 10^{-34} \mathrm{~Js}, e=1.6 \times 10^{-19} \mathrm{C}$)

A $P$-type semiconductor has acceptor levels $57\;meV$ above the valence band. The maximum wavelength of light required to create a hole is (Planck’s constant $h = 6.6 \times {10^{ - 34}}J$-s)

Which of the following logic gate is an universal gate

The equivalent decimal number of binary number ${\left( {11001.001} \right)_2}$ is

If the forward voltage in a semiconductor diode is changed from 0.5 V to 0.7 V, then the forward current changes by 1.0 mA. The forward resistance of diode junction will be