Semi conductor devices practice · Medium

When the reverse bias in a junction diode is changed from 5V to 15V, the value of current changes from $38\,\mu A$ to $88\,\mu A$. The reverse resistance of the junction diode will be

A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of

If a transistor, the emitter, base and collector are respectively

Statement-I: A $\mathrm{p-n}$ junction with reverse bias can be used as a photodiode to measure light intensity.

Statement-II: In a reverse bias condition the current is small but it is more sensitive to changes in incident light intensity.

A piece of copper and another of germanium are cooled from temperature to $80^\circ \,K.$ The resistance of

Bonding in a germanium crystal (semi-conductor) is

Electric conduction in semi-conductor takes place due to

Let ${n_p}\,\,{\text{and }}{n_e}$ be the number of holes and conduction electrons in an intrinsic semiconductor. Then

In order to forward bias a $PN$ junction, the negative terminal of battery is connected to

In an $n$-type semiconductor, the fermi energy level lies

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

If ${n_e}$ and ${v_d}$ be the number of electrons and drift velocity in a semiconductor. When the temperature is increased

$C$ and $Si$ both have same lattice structure, having 4 bonding electrons in each. However, $C$ is insulator where as Si is intrinsic semiconductor. This is because

In semiconductors at room temperature: -

$\overline{A \cdot \bar{B}+\bar{A} \cdot B}$ is equivalent to

Zener diodes have higher dopant densities as compared to ordinary p-n junction diodes. This

Statement A: In intrinsic semiconductors, conductivity is mainly due to the breakage of covalent bonds.
Statement B: In extrinsic semiconductors, the conductivity is mainly due to the addition of impurities.

When a P-N junction is forward biased, the flow of current across the junction is mainly due to

For germanium crystal, the forbidden energy gap in joules is

For LED’s to emit light in visible region of electromagnetic light, it should have energy band gap in the range of:

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

For a transistor $\alpha$ and $\beta$ are given as $\alpha = \frac{{{I_C}}}{{{I_E}}}$ and $\beta = \frac{{{I_C}}}{{{I_E}}}$. Then, the correct relation between $\alpha$ and $\beta$ will be

In forward bias, the width of potential barrier in a $P$-$N$ junction diode

In BJT, maximum current flows in which of the following?

Three amplifier stages each with a gain of 10 are cascaded. The overall gain is

The coordination number of $Cu$ is

The logic behind ‘NOR’ gate is that it gives

Which of the following is not equal to 1 in Boolean algebra?

The band gap in germanium and silicon in $eV$ respectively is

A semiconducting material has a band gap of $1 \mathrm{~eV}$. Acceptor impurities are doped into it which create acceptor levels $1 \mathrm{~meV}$ above the valence band. Assume that the transition from one energy level to the other is almost forbidden if $k T$ is less than $1 / 50$ of the energy gap. Also, if $k T$ is more than twice the gap, the upper levels have maximum population. The temperature of the semiconductor is increased from $0 \mathrm{~K}$. The concentration of the holes increases with temperature and after a certain temperature it becomes approximately constant. As the temperature is further increased, the hole concentration again starts increasing at a certain temperature. Find the order of the temperature range in which the hole concentration remains approximately constant.