1. The color code of a 1 kiloohm resistance is
a) black , brown , red
b) red, brown, brown
c) brown, black, red
d) black, black , red
ans. c
2. An electron with velocity u is placed in an electric field E and magnetic field B. The force experienced by the electron is given by
a) -eE
b) -eu X B
c) -e(u X E + B)
d) -e(E + u X B)
ans. d
3. The primary reason for the widespread use of Silicon semiconductor device technology is
a) abundance of Silicon on the surface of Earth.
b) larger bandgap of Silicon in comparison to Germanium.
c) favourable properties of Silicon-dioxide (Sio2).
d) lower melting point.
ans. a
4. A Silicon wafer has 100 nm of oxide on it and is inserted in a furnace at a temperature above 1000 degree centigrade for further oxidation in dry oxygen. The oxidation rate is
a) independent of current , oxide thickness and temperature.
b) independent of current, oxide thickness but depends on temperature.
c) slows down as the oxide grows.
d) zero as the existing oxide prevents further oxidations.
ans. d
5. The band gap of silicon at room temperature is
a) 1.3 eV
b) 0.7 eV
c) 1.1 eV
d) 1.4 eV
ans. c
6. n-type silicon is obtained by doping silicon with
a) Germanium
b) Aluminium
c) Boron
d) Phosporous
ans. d
7. Which of the following is true ?
a) A silicon wafer heavily doped with boron is a p+ substrate.
b) A silicon wafer lightly doped with boron is a p+ substrate.
c) A silicon wafer heavily doped with Arsenic is a p+ substrate.
d) A silicon wafer lightly doped with Arsenic is a p+ substrate.
ans. a
8. The concentration of minority carriers in an extrinsic semiconductor under equilibrium is
a) directly proportional to the doping concentration.
b) inversely proportional to the doping concentration.
c) directly proportional to the intrinsic concentration.
d) inversely proportional to the intrinsic concentration.
ans. b
9. Under low level injection assumption, the injected minority carrier current for an extrinsic semiconductor is essentially the
a) diffusion current
b) drift current
c) recombination current
d) induced current
ans. a
10. The majority carriers in an n-type semiconductor have an average drift velocity in a direction perpendicular to a uniform magnetic field B. The electric field E induced due to Hall effect acts in the direction .
a) v X B
b) B X v
c) along v
d) opposite to v
ans. b
a) black , brown , red
b) red, brown, brown
c) brown, black, red
d) black, black , red
ans. c
2. An electron with velocity u is placed in an electric field E and magnetic field B. The force experienced by the electron is given by
a) -eE
b) -eu X B
c) -e(u X E + B)
d) -e(E + u X B)
ans. d
3. The primary reason for the widespread use of Silicon semiconductor device technology is
a) abundance of Silicon on the surface of Earth.
b) larger bandgap of Silicon in comparison to Germanium.
c) favourable properties of Silicon-dioxide (Sio2).
d) lower melting point.
ans. a
4. A Silicon wafer has 100 nm of oxide on it and is inserted in a furnace at a temperature above 1000 degree centigrade for further oxidation in dry oxygen. The oxidation rate is
a) independent of current , oxide thickness and temperature.
b) independent of current, oxide thickness but depends on temperature.
c) slows down as the oxide grows.
d) zero as the existing oxide prevents further oxidations.
ans. d
5. The band gap of silicon at room temperature is
a) 1.3 eV
b) 0.7 eV
c) 1.1 eV
d) 1.4 eV
ans. c
6. n-type silicon is obtained by doping silicon with
a) Germanium
b) Aluminium
c) Boron
d) Phosporous
ans. d
7. Which of the following is true ?
a) A silicon wafer heavily doped with boron is a p+ substrate.
b) A silicon wafer lightly doped with boron is a p+ substrate.
c) A silicon wafer heavily doped with Arsenic is a p+ substrate.
d) A silicon wafer lightly doped with Arsenic is a p+ substrate.
ans. a
8. The concentration of minority carriers in an extrinsic semiconductor under equilibrium is
a) directly proportional to the doping concentration.
b) inversely proportional to the doping concentration.
c) directly proportional to the intrinsic concentration.
d) inversely proportional to the intrinsic concentration.
ans. b
9. Under low level injection assumption, the injected minority carrier current for an extrinsic semiconductor is essentially the
a) diffusion current
b) drift current
c) recombination current
d) induced current
ans. a
10. The majority carriers in an n-type semiconductor have an average drift velocity in a direction perpendicular to a uniform magnetic field B. The electric field E induced due to Hall effect acts in the direction .
a) v X B
b) B X v
c) along v
d) opposite to v
ans. b
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