What is the effect of doping on semiconductor conductivity?
A Decreases
B No effect
C Increases resistance
D Increases
Doping introduces impurities into a semiconductor, which increases the number of charge carriers (electrons or holes). This improves the conductivity of the semiconductor, making it more efficient for electronic devices.
What are the majority carriers in a p type semiconductor?
A Holes
B Electrons
C Protons
D Neutrons
In a p type semiconductor, holes are the majority carriers. These holes are created by the absence of electrons in the valence band, and they carry positive charge, allowing current to flow through the material.
What is the role of minority carriers in a semiconductor?
A Increase resistance
B Carry the reverse current
C Increase current
D Control conductivity
Minority carriers in a semiconductor are charge carriers (electrons in p type, holes in n type) that exist in lower concentrations. They contribute to reverse current when a semiconductor device is reverse biased, such as in a diode.
What is the main purpose of a pn junction diode?
A Signal amplification
B Voltage modulation
C Current rectification
D Signal switching
A pn junction diode is designed to allow current to flow in only one direction, effectively rectifying alternating current (AC) to direct current (DC). This property is crucial in power supplies and other electronic circuits.
How does doping a semiconductor with Group V elements (like phosphorus) affect its conductivity?
A Increases conductivity
B Decreases conductivity
C No effect
D Changes resistance
Doping a semiconductor with Group V elements, such as phosphorus, introduces extra electrons that increase the number of free charge carriers. This turns the semiconductor into an n type material, enhancing its conductivity.
What does the term “intrinsic semiconductor” refer to?
A Doped semiconductor
B Semiconductor with high resistivity
C Pure semiconductor
D Semiconductor with low resistance
An intrinsic semiconductor is a pure material that has not been doped with impurities. Its conductivity is determined by thermal excitation, where electrons are excited from the valence band to the conduction band.
What is the primary charge carrier in an n type semiconductor?
A Electrons
B Holes
C Protons
D Neutrons
In an n type semiconductor, electrons are the majority charge carriers. These electrons are donated by donor atoms during doping, and they facilitate electrical conduction through the material.
What is the main function of a Zener diode?
A Signal amplification
B Current rectification
C Voltage regulation
D Light emission
A Zener diode is used for voltage regulation. It allows current to flow normally in the forward direction, but in reverse bias, it maintains a constant voltage across it, making it ideal for voltage reference applications.
What is the role of the base in a Bipolar Junction Transistor (BJT)?
A Emit charge carriers
B Control current flow
C Collect charge carriers
D Amplify signals
The base of a BJT controls the flow of charge carriers between the emitter and the collector. A small base current enables a larger current to flow through the collector–emitter junction, allowing signal amplification.
What happens when the temperature of a semiconductor increases?
A Carrier concentration increases
B Carrier concentration decreases
C Carrier mobility decreases
D Resistance decreases
As temperature increases, more electrons gain enough energy to jump from the valence band to the conduction band, increasing the carrier concentration. This results in higher conductivity in the semiconductor.
What does the Hall effect measure in a semiconductor?
A Voltage drop
B Carrier concentration
C Magnetic field
D Electric current
The Hall effect is the generation of a transverse voltage when a current carrying conductor or semiconductor is exposed to a magnetic field. It can be used to measure the strength of the magnetic field and to determine carrier concentration.
What is the effect of increasing the doping concentration in a semiconductor?
A Increases resistivity
B Decreases conductivity
C No effect on conductivity
D Increases conductivity
Increasing the doping concentration in a semiconductor introduces more charge carriers (electrons or holes), which increases the material’s electrical conductivity. This is essential for creating semiconductors with desired electrical properties.
Which of the following is true for an n type semiconductor?
A Majority carriers are holes
B Doped with acceptor atoms
C Majority carriers are electrons
D Has high resistivity
In an n type semiconductor, electrons are the majority charge carriers. This is because the semiconductor is doped with donor atoms, which provide extra electrons, increasing conductivity.
What is the typical application of a photodiode?
A Signal amplification
B Light detection
C Voltage regulation
D Current rectification
A photodiode is designed to detect light and convert it into electrical current. It operates in reverse bias and generates current when illuminated, making it essential in optical sensing and communication systems.
What defines the efficiency of a solar cell?
A Conversion of light to electrical energy
B Voltage
C Current
D Power output
The efficiency of a solar cell is defined by how effectively it converts sunlight into electrical energy. Factors such as material properties, cell design, and light absorption affect the overall conversion efficiency.