31 Year NEET Previous Year Questions: Semiconductor Electronics - 4 - NEET MCQ

For forward biasing of p-n junction, the
positive terminal of external battery is to be
connected to p-semiconductor and negative
terminal of battery to the n-semiconductor.

Semiconductors are insulators at room
temperature

Due to heating, when a free electron is
produced then simultaneously a hole is also
produced.

Radiowaves of constant amplitude can be
produced by using oscillator with proper
feedback.

The phase difference between output
voltage and input signal voltage in common
base transistor or circuit is zero.

Voltage gain of an amplifier

The negative sign indicates that the output
voltage differs in phase from the input
voltage by 180°(or π). This holds for a pure
resistive load.

The depletion layer in the p-n junction region
is caused by diffusion of charge carriers.

This truth table is of identity, X = A + B, hence
OR gate.

To use a transistor as an amplifier the emitter
base junction is forward biased while the
collector base junction is reverse biased

Vander Waal’s bonding is the weakest
bonding in solids

The amplifying action of a triode is based on
the fact that a small change in grid voltage
causes a large change in plate current. The
AC input signal which is to be amplified is
superimposed on the grid potential.

According to Child’s Law,

Copper is a conductor, so, its resistance
decreases on decreasing temperature as
thermal agitation decreases whereas
germanium is semiconductor, therefore, on
decreasing temperature resistance increases.

Diamond is very hard due to large cohesive
energy.

The function of emitter is to supply the
majority carriers. So, it is heavily doped

A positive feed back from output to input in
an amplifier provides oscillations of constant
amplitude.

When p-n junction is reverse biased, the flow
of current is due to drifting of minority charge
carriers across the junction.

It is the circuit of full wave rectifier.

This truth table is of the identity,    hence it is NAND gate.
Here, the output is high even if all inputs are low or one input is low.

The given circuit is a circuit of full wave
rectifier.

Phosphorous (P) is pentavalent and silicon
is tetravalent. Therefore, when silicon is
doped with pentavalent impurity, it forms a
n-type semiconductor.

Current gain (α) = 0.96

In an n-p-n transistor, the charge carriers,
are free electrons in the transistor as well as
in external circuit; these electrons flow from
emitter to collector

Arsenic contains 5 electrons in its outermost
shell. When Arsenic is mixed with silicon
there is one electron extra in silicon crystal.
Hence, such type of semi conductor is ntype
semi conductor

p-type germanium semiconductor is formed
when it is doped with a trivalent impurity
atom.