Practice Test: Question Set - 07
1. For a hole which of the following statements is incorrect?
- (A) Holes can exist in certain semiconductors
only
- (B) Holes can exist in any material including
conductors
- (C) Holes may constitute an electric current
- (D) Holes can be considered as a net positive
charge
2. Thermocouples are mainly used for the measurement of
- (A) Temperature
- (B) Resistance
- (C) Eddy currents
- (D) Coupling coefficient
3. The impurity atoms is semiconductors
- (A) Inject more charge carriers
- (B) Reduce the energy gap
- (C) Increase the kinetic energy of valence
electrons
- (D) All of the above
4. ________ is a hard solder.
- (A) Tin-lead
- (B) Tin-silver-lead
- (C) Copper-zinc
- (D) None of the above
5. At transition temperature the value of critical field is
- (A) Zero
- (B) Negative real value
- (C) Positive real value
- (D) Complex value
6. The conductivity of a conductor can be increased by
- (A) Decreasing its temperature
- (B) Increasing its temperature
- (C) Decreasing its vibration
- (D) Increasing its vibration
7. The formula _______ determines the number of electrons that can be accommodated in any level.
- (A) 2n2
- (B) 4n2
- (C) 2n3
- (D) 4n4
8. Due to which of the following reasons aluminium does not corrode in atmosphere?
- (A) Aluminium is a noble metal
- (B) Atmospheric oxygen can only diffuse very slowly
through the oxide layer which is formed on the surface of aluminium
- (C) No reaction with oxygen occurs
- (D) Any of the above
9. Which of the following is a semiconductor material?
- (A) Phosphorous
- (B) Rubber
- (C) Silicon
- (D) Aluminium
10. The conductivity of an extrinsic semiconductor with temperature
- (A) Decreases
- (B) Increases
- (C) Remains constant
- (D) None of the above
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