Semi conductor devices practice · Mixed difficulty

Assertion: If the temperature of semiconductor is increases then its resistance decreases.

Reason: The energy gap between conduction band and valence band is small.

Statement-I: Germanium is preferred over silicon for making semiconductor devices.

Statement-II: Energy gap for Ge is more than that of ${Si}$.

Pure sodium $\left( {Na} \right)$ is a good conductor of electricity because the $3s$ and $3p$ atomic bands overlap to form a partially filled conduction band. By contrast the ionic sodium chloride $\left( {NaCl} \right)$ crystal is

Electrical conductivity of a semiconductor

Which of the following statements is true for an $n$-type semiconductor?

Given below are two statements:
Statement-I: Carbon $(\mathrm{C})$, Silicon $(\mathrm{Si})$, Germanium $(\mathrm{Ge})$ have same lattice structure. But $\mathrm{C}$ is semiconductor $\&\, \mathrm{Si}, \mathrm{Ge}$ are insulators.
Statement-II: Ionisation energy is least for $\mathrm{C}$ followed by $\mathrm{Si}, \mathrm{Ge}$.

The reverse biasing in a $PN$ junction diode

As $n$-type and a $p$-type silicon semiconductor can be obtained by doing pure silicon with

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

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

A transistor operating in common emitter configuration $\&$ change in base current from $200\, \mu {A}$ to $250 \,\mu {A}$ produces change in collector current from $10 \,{~mA}$ to $15 \,{~mA}$. The current gain is

The coordination number of hexagonal close packing (hcp) is

How many NAND gates are used in an OR gate?

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.

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

Statement-II: In transistor, sum of base current and collector current is equal to emitter current.

In a transistor the base is made very thin and is lightly doped with an impurity because –

Assertion : Metals are better conductor than semiconductors.

Reason : Valence band and conduction band have large energy gap in case of metals.

If the forward voltage in a diode is increased, the width of the depletion region

Bonds in semiconductor are

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

The coordination number of simple cubic crystal is

What is the value of $A - \overline A$ in Boolean algebra?

When boron is added as an impurity to silicon, the resulting material is

Electronic configuration of germanium is 2, 8, 18 and 4. To make it extrinsic semiconductor small quantity of antimony is added

Donor type impurity is found in

The energy gap between conduction band and the valence band is of the order of 0.7 eV. Then it is

Formation of covalent bonds in compounds exhibits

In a semiconducting material the mobilities of electrons and holes are ${\mu _e}$ and ${\mu _h}$ respectively. Which of the following is true

In $NPN$ transistor, if doping in base region is increased then collector current

Suppose an unregulated d.c. input voltage ${V_I}$ is applied to a Zener diode having breakdown voltage$\left( {{V_z}} \right)$. Then the breakdown condition for the diode to work as voltage regulator is