Semiconductors and Energy Bands Quiz
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Questions and Answers

What replaces Cathode Ray Tubes in modern displays?

  • OLED Screens
  • Plasma Displays
  • LED Displays
  • Liquid Crystal Displays (correct)
  • What is defined as the energy gap between the valence band and the conduction band?

  • Energy Gap (correct)
  • Conduction Gap
  • Valence Band Gap
  • Forbidden Energy Zone
  • In a semiconductor, how do electrons behave in the conduction band?

  • They are tightly bound within the atoms.
  • They can only move at absolute zero temperature.
  • They cannot transition back to the valence band.
  • They are free to move and contribute to electrical current. (correct)
  • What characterizes an insulator in terms of energy bands?

    <p>Wide energy gap</p> Signup and view all the answers

    What does the term 'forbidden energy gap' refer to?

    <p>The energy gap between the valence band and conduction band</p> Signup and view all the answers

    How does temperature affect the conductivity of semiconductors?

    <p>Conductivity increases with higher temperature.</p> Signup and view all the answers

    Which statement about the conduction band in semiconductors is correct?

    <p>It may be empty or partially filled.</p> Signup and view all the answers

    What is meant by the term 'valence band'?

    <p>A band that may be completely filled with electrons</p> Signup and view all the answers

    Which of the following describes metals in terms of energy bands?

    <p>Electrons are in a partially filled conduction band.</p> Signup and view all the answers

    What does Eg represent in the context of semiconductors?

    <p>Energy gap energy</p> Signup and view all the answers

    What is the primary function of rectifiers?

    <p>Convert AC to DC voltage</p> Signup and view all the answers

    What is the output frequency of full-wave rectifiers in relation to the input frequency?

    <p>Twice the input frequency</p> Signup and view all the answers

    What is the characteristic of Zener diodes regarding current?

    <p>Zener voltage remains constant through varying current</p> Signup and view all the answers

    What type of biasing do photodiodes typically operate under?

    <p>Reverse bias</p> Signup and view all the answers

    What is the main difference between LEDs and regular junction diodes?

    <p>LEDs emit light when energized</p> Signup and view all the answers

    What does a solar cell aim to convert?

    <p>Energy into electrical energy</p> Signup and view all the answers

    In the formula for normal voltage ($V_n = \frac{kT}{q}$), which variable represents the charge?

    <p>q</p> Signup and view all the answers

    What does the reverse saturation current (I) depend on according to the formula $I = I_0 e^{\frac{V}{kT}}$?

    <p>Voltage and temperature</p> Signup and view all the answers

    What is the formula for current density (J) for electrons?

    <p>J = q , n , \mu_n , E</p> Signup and view all the answers

    Which materials are used in the fabrication of LEDs?

    <p>Gallium-based semiconductors</p> Signup and view all the answers

    What type of impurity creates n-type semiconductors?

    <p>Pentavalent impurity</p> Signup and view all the answers

    In which type of semiconductor are holes the majority carriers?

    <p>p-type semiconductor</p> Signup and view all the answers

    What happens to the effective barrier potential in reverse bias?

    <p>It increases.</p> Signup and view all the answers

    Which of the following diodes is used as a voltage regulator?

    <p>Zener diode</p> Signup and view all the answers

    What is the primary function of a half-wave rectifier?

    <p>Convert ac voltage to dc voltage.</p> Signup and view all the answers

    Which of the following characterizes intrinsic semiconductors?

    <p>Behaves as an insulator</p> Signup and view all the answers

    What effect does forward bias have on a diode?

    <p>Effective barrier potential decreases.</p> Signup and view all the answers

    What is the primary characteristic of a photodiode?

    <p>Converts light energy into electrical current</p> Signup and view all the answers

    What is true about n-type semiconductors concerning their charge neutrality?

    <p>They are neutral overall.</p> Signup and view all the answers

    What is a characteristic feature of full-wave rectifiers compared to half-wave rectifiers?

    <p>They convert both half-cycles into pulsating dc.</p> Signup and view all the answers

    What is the equation for Electric Current in terms of the effective masses of electrons and holes?

    <p>I = $CA( rac{ ext{m}V_e}{ ext{m}V_h}) + rac{ ext{m}V_h}{ ext{m}V_e}$</p> Signup and view all the answers

    What is the formula for the dynamic resistance of a p-n junction?

    <p>R_d = $ rac{ ext{d}V}{ ext{d}I}$</p> Signup and view all the answers

    In a common emitter amplifier, what is the formula for voltage gain?

    <p>$ rac{ ext{V}_o}{ ext{V}_i} = eta imes R_L$</p> Signup and view all the answers

    What does the output DC voltage in a transistor depend on?

    <p>$ ext{Jac} imes R imes rac{2 imes ext{pi}}{ ext{pi}}$</p> Signup and view all the answers

    What is the relationship between collector current and emitter current in a transistor?

    <p>$I_c = I_e - I_b$</p> Signup and view all the answers

    Which logic gate is represented by the expression $A imes B = Y$?

    <p>AND gate</p> Signup and view all the answers

    What is the equation for the voltage gain of a common base amplifier?

    <p>$ rac{ ext{V}_o}{ ext{V}_i} = rac{ ext{d}V_o}{ ext{d}V_i}$</p> Signup and view all the answers

    What is the output of the XOR gate according to its logical expression?

    <p>True when inputs are different</p> Signup and view all the answers

    In rectification, what does the mean load current primarily depend on?

    <p>Half wave rectified current</p> Signup and view all the answers

    How is the output of a NAND gate defined mathematically?

    <p>$ar{(A imes B)} = Y$</p> Signup and view all the answers

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