Self Studies
Self Studies
Self Studies
Self Studies

Semiconductor Electronics: Materials, Devices and Simple Circuits Test 5

Result Self Studies

Semiconductor Electronics: Materials, Devices and Simple Circuits Test 5
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0
    The main cause of Zener breakdown is
    Solution
    Zener breakdown occurs in heavily doped p-n junctions. The heavy doping makes the depletion layer extremely thin. So that, carriers cannot accelerate enough to cause ionization. Thus, current will increase in reverse bias only due to reverse breakdown voltage.
  • Question 2
    1 / -0
    When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called
    Solution
    At room temperature, in impure semiconductors some free charge carriers are available for conduction due to impurity atoms. But in pure, i.e., intrinsic semiconductors, $$n=p$$. Hence, at room temperature no free electrons are available for conduction. If the temperature is increased the covalent bonds will break and electrons will be freed, each electron will leave behind a hole and capture a new hole the process will continued and charge flows through intrinsic semiconductor. Thus, its conductivity is only due to breaking of covalent bonds.
  • Question 3
    1 / -0
    The main cause of avalanche breakdown is
    Solution
    Avalanche breakdown is caused by impact ionization of electron-hole pairs. A very little current flows under reverse bias conditions and depletion region increases. The electric field in the depletion region of a diode can be very high. Electron/holes that enter the depletion region undergo a tremendous acceleration. As these accelerated carriers collide with the atoms, they can knock electrons from their bonds, creating additional electron/hole pairs and thus additional current. As these secondary carriers are swept into the depletion region, they too are accelerated and the process repeats itself.
  • Question 4
    1 / -0
    In an intrinsic semiconductor, conductivity is
    Solution
    In intrinsic semiconductors, $$n = p$$. Hence, at room temperature, no free electrons are available for conduction. If the temperature is increased, the covalent bonds will break and electrons will be freed, each electron will leave behind a hole and capture a new hole the process will continued and charge flows through intrinsic semiconductor. Thus, its conductivity increases with temperature. Hence, in intrinsic semiconductor conductivity is low at room temperature.
  • Question 5
    1 / -0
    In semiconductors, at a room temperature
    Solution
    In semiconductors at room temperature the electrons get enough energy so that they are able to over come the forbidden gap. Thus at room temperature the valence band is partially empty and conduction band is partially filled.
  • Question 6
    1 / -0
    In an intrinsic semiconductor, the Fermi energy level is
    Solution
    Fermi energy is determined as the energy point where the probability of occupancy by an electron is exactly $$50%$$ or $$0.5$$, i.e., $$\dfrac{1}{2}$$. For the intrinsic semiconductor, since electrons and holes are always created in pairs, $$n = p = ni$$. Hence, there are equal number of holes and electrons in valence band and conduction band respectively. Therefore, the Fermi energy level is equidistant from conduction band and valence band.
  • Question 7
    1 / -0
    The current flow in a Zener diode is mainly due to
    Solution
    When the reverse bias breakdown voltage is exceeded, a conventional diode is subject to high current due to avalanche breakdown. Avalanche breakdown occurs in reverse bias when the applied voltage is high enough, the free electron may move fast enough to knock other electrons free, creating more free-electron-hole pairs (i.e., more charge carriers), increasing the current. Thus, the current flow in a Zener diode is mainly due to collision generated charge carriers
  • Question 8
    1 / -0
    A Zener diode
    Solution
    The reverse breakdown voltage depends on doping of the diode. Hence, in the Zener diode the heavy doping of its p-n junction is done. The depletion region formed in the diode is very thin ($$<1\ m$$) and the reverse bias voltage of about $$5\ V$$ which is less than ordinary diode.
  • Question 9
    1 / -0
    In an intrinsic semiconductor, conductivity is due to
    Solution
    In intrinsic semiconductors, $$n = p$$. Hence, at room temperature, no free electrons are available for conduction. If some energy is supplied to the atoms of intrinsic semiconductor, the covalent bonds will break and electrons will be freed, each electron will leave behind a hole and capture a new hole the process will continued and charge flows through intrinsic semiconductor. Thus, in intrinsic semiconductor conductivity is due to breaking of covalent bonds.
  • Question 10
    1 / -0
    p-n junction diode can be used as
    Solution
    A p-n junction in the form of photo diode is used in detectors, sensors etc.
Self Studies
User
Question Analysis

  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now