3. Semiconductors are materials that
have electrical conductivity
between that of conductors (like
metals) and insulators (like non-
metals). The conductivity of
semiconductors can be controlled
and modified by factors such as
temperature, impurities, or the
application of an external electric
field. Unlike conductors, which
have high conductivity, and
insulators, which have low
conductivity, semiconductors have
an intermediate level of
conductivity.
4. Semiconductors are materials that
have electrical conductivity
between that of conductors (like
metals) and insulators (like non-
metals). The conductivity of
semiconductors can be controlled
and modified by factors such as
temperature, impurities, or the
application of an external electric
field. Unlike conductors, which
have high conductivity, and
insulators, which have low
conductivity, semiconductors have
an intermediate level of
conductivity.
One of the defining features of semiconductors is their ability to carry an
electric current under certain conditions and to act as a switch, turning
the flow of current on or off. This property makes semiconductors a
crucial component in the field of electronics, where they are extensively
used in devices such as transistors, diodes, and integrated circuits. The
electrical properties of semiconductors are often manipulated through
processes like doping, which involves introducing specific impurities into
the semiconductor material to enhance its conductivity or alter its
electrical behavior. Silicon and germanium are common examples of
semiconductors widely used in the electronics industry.
6. PHOTOELE
-CTRIC
EFFECT
Photoelectric Effect:
•Definition: The photoelectric effect is the phenomenon where electrons
are emitted from a material when it is exposed to light or electromagnetic
radiation.
•Key Points: It involves the absorption of photons, and the emitted
electrons' energy depends on the frequency of the incident light. This
effect played a crucial role in the development of quantum theory.
7. THERMOELE
-CTRIC
EFFECT
Thermoelectric Effect:
•Definition: The thermoelectric effect refers to the generation of an electric voltage
or current in a material when there is a temperature difference between two points.
•Key Points: It is based on the Seebeck effect, where a temperature gradient
across a material induces the flow of charge carriers, creating a voltage. This
phenomenon is utilized in thermoelectric generators for converting heat into
electricity.
8. Commutating Action
Definition: "Commutating action" is not a widely recognized term in physics, and
its meaning might depend on the specific context in which it's used. In general
electrical engineering terms, "commutating" often refers to the process of
reversing the direction of current or voltage.
COMMUNIC-
ATING
ACTION
9. Hall effect
•Definition: The Hall effect is a phenomenon where a voltage is generated
perpendicular to the direction of an electric current and an applied magnetic
field in a conductor or semiconductor.
•Key Points: It occurs when charged particles (usually electrons) experience a
force due to the magnetic field, causing them to accumulate on one side of the
conductor. The Hall effect is used to measure the strength of magnetic fields, as
well as to determine the type and concentration of charge carriers in a material.
HALL EFFECT
