Question 1 The most commonly used semiconductor is ………
- Germanium
- Silicon
- Carbon
- Sulphur
Answer – Silicon
Question 2 The resistivity of a pure silicon is about ……………
- 100 Ω cm
- 6000 Ω cm
- 3 x 105 Ω m
- 6 x 10-8 Ω cm
Answer – 6000 Ω cm
Question 3 A semiconductor is formed by ……… bonds.
- Covalent
- Electrovalent
- Co-ordinate
- None of the above
Answer – Covalent
Question 4 A pentavalent impurity has ………. Valence electrons
- 3
- 5
- 4
- 6
Answer – 5
Question 5 A semiconductor has generally ……………… valence electrons.
- 2
- 3
- 6
- 4
Answer – 4
Question 6 A hole in a semiconductor is defined as …………….
- A free electron
- The incomplete part of an electron pair bond
- A free proton
- A free neutron
Answer – The incomplete part of an electron pair bond
Question 7 Addition of trivalent impurity to a semiconductor creates many ……..
- Holes
- Free electrons
- Valence electrons
- Bound electrons
Answer – Holes
Question 8 Addition of pentavalent impurity to a semiconductor creates many ……..
- Free electrons
- Holes
- Valence electrons
- Bound electrons
Answer – Free electrons
Question 9 In a semiconductor, current conduction is due to …
- Only holes
- Only free electrons
- Holes and free electrons
- None of the above
Answer – Holes and free electrons
Question 10 The battery connections required to forward bias a pn junction are ……
- +ve terminal to p and –ve terminal to n
- -ve terminal to p and +ve terminal to n
- -ve terminal to p and –ve terminal to n
- None of the above
Answer – +ve terminal to p and –ve terminal to n
Question 11 A forward biased pn junction diode has a resistance of the order of
- Ω
- kΩ
- MΩ
- None of the above
Answer – Ω
Question 12 The barrier voltage at a pn junction for germanium is about ………
- 5 V
- 3 V
- Zero
- 0.3 V
Answer – 0.3 V
Question 13 A reverse bias pn junction has …………
- Very narrow depletion layer
- Almost no current
- Very low resistance
- Large current flow
Answer – Almost no current
Question 14 A pn junction acts as a ……….
- Controlled switch
- Bidirectional switch
- Unidirectional switch
- None of the above
Answer – Unidirectional switch
Question 15 In the depletion region of a pn junction, there is a shortage of ……..
- Acceptor ions
- Holes and electrons
- Donor ions
- None of the above
Answer – Holes and electrons
Question 16 The leakage current across a pn junction is due to …
- Minority carriers
- Majority carriers
- Junction capacitance
- None of the above
Answer – Minority carriers
Question 17 When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on……
- Junction capacitance
- Minority carriers
- Majority carriers
- None of the above
Answer – Minority carriers
Question 18 With forward bias to a pn junction , the width of depletion layer ………
- Decreases
- Increases
- Remains the same
- None of the above
Answer – Decreases
Question 19 At room temperature, an intrinsic semiconductor has ……….
- Many holes only
- A few free electrons and holes
- Many free electrons only
- No holes or free electron
Answer – A few free electrons and holes
Question 20 The leakage current in a pn junction is of the order of
- Aa
- mA
- kA
- µA
Answer – µA
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FAQ – Frequently ask questions
Which is most commonly used semiconductor?
Silicon, Silicon is the most used semiconductor in power electronic components like diodes, thyristors, IGBT, MOSFET transistors.
How Semiconductor form?
A semiconductor is form by covalent bond with his neighboring atoms.
In covalent bonding each valence electron is shared by two atoms
In covalent bonding each valence electron is shared by two atoms
How many valence electrons in a pentavalent impurity atom?
In pentavalent impurity atom 5 valence electron in their outer most cell
How pn junction acts?
pn junction acts as a unidirectional switch
In a pn junction leakage current is due to
Minority carriers