1. The Covalent bond is formed by:
a) Transfer of electrons between the atoms
b) Sharing of electrons between the atoms
c) Sharing of variable number of electrons by a variable number of atoms
d) Removing the electrons completely
2. In a conductor the valence band and the conduction band
a) Separated by large gap
b) Separated by small gap
c) Overlapping
d) None of the above
3.A Thyratron is a:
a) Gas filled diode
b) Gas filled triode
c) Gas filled tetrode
d) Gas filled pentode
4. A Vacuum diode is a:
i) Detector
ii) Rectifier
iii) Amplifier
iv) Oscillator
of all these statements:
a) (i) and (ii) are correct
b) (ii) and (iii) are correct
c) (ii) and (iv) are correct
d) (i) and (iv) are correct
5. A practical current source is usually represented by:
a) Resistance in series with an ideal current source
b) Resistance in parallel with an ideal current source
c) Resistance in both series and parallel with ideal current sourcce
d) Resistance and capacitor in parallel with the ideal current source
6. The process of electron emission from the surface of a metal into the surrounding space by heating the material is known as:
a) Thermionic emission
b) Secondary emission
c) Field emission
d) Photo-electronic emission
7. An ideal voltage source will charge an ideal capacitor:
a) In infinite time
b) Exponentially
c) Instantaneously
d) None of the above
8. An example of solid state device is:
a) Zener diode
b) Triode
c) Pentode
d) Thyratron
9.In Zener diode large reverse current is due to:
a) Collision
b) Presence of impurities
c) Rupture of bonds
d) Low resistance in the reverse biased region
10. Avalanche breakdown in a semiconductor diode occurs when:
a) The potential barrier is reduced to zero
b) Reverse bias exceeds a certain value
c) Forward bias exceeds a certain value
d) Forward current exceeds certain value
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