Electrical Engineering Materials Multiple Choice Questions and Answers-1 (English)

1. Which of the following material is not a semiconductor ?
(A) Silica
(B) Germanium
(C) Selenium
(D) Gallium-arsenide
Ans: (A) Silica

2. Which of the following are non-conductors of electricity?
(A) Non-metal solids except carbon
(B) Air and most other gases
(C) Pure water and liquids in general except mercury
(D) All of the above
Ans: (D) All of the above

3. Steel wire is used as
(A) overhead telephone wire
(B) earth wire
(C) core wire of ACSR
(D) all of the above
Ans: (D) all of the above

4. Platinum is used in
(A) electrical contacts
(B) thermocouple
(C) heating element in high temperature furnace
(D) grids of special purpose vacuum tubes
(e) all of the above
Ans: (e) all of the above

5. Which of the following materials is used for making coils of standard resistances ?
(A) Copper
(B) Nichrome
(C) Platinum
(D) Manganin
Ans: (D) Manganin

6. is the property of absorbing moisture from atmosphere.
(A) Solubility
(B) Viscosity
(C) Porosity
(D) Hygroscopicity
Ans: (D) Hygroscopicity

7. Which of the following is a semiconductor material ?
(A) Phosphorous
(B) Rubber
(C) Silicon
(D) Aluminium
Ans: (C) Silicon

8. Selenium is _____ semiconductor.
(A) extrnisic
(B) intmisic
(C) N-type
(D) P-type
Ans: (B) intmisic

9. Spark plug makes use of which of the following materials for insulation ?
(A) Porcelain
(B) Slate
(C) Asbestos
(D) Glass
Ans:(A) Porcelain

10. Superconducting metal in super conducting state has relative permeability of
(A) zero
(B) one
(C) negative
(D) more than one
Ans: (A) zero

11. In graphite, bonding is
(A) covalent
(B) metallic
(C) Vander Waals
(D) Vander Waals and covalent
Ans: (D) Vander Waals and covalent

12. Total number of crystal systems is
(A) 2
(B) 4
(C) 7
(D) 12
Ans: (C) 7

13. The number of atoms per unit cell in B.C.C. structure is
(A) 1
(B) 2
(C) 4
(D) 8
Ans: (D) 8

14. Carbon resistors are used extensively because they are
(A) easy to make
(B) compact
(C) inexpensive
(D) all of the above reasons
Ans: (D) all of the above reasons

15. Carbon rods are used in wet and dry cells because
(A) carbon rod serves as conductor
(B) carbon can resist the attack of battery acid
(C) both (A) and (b)
(D) either (A) or (b)
Ans: (C) both (A) and (b)

16. Due to which of the following factors the brush wear rate is altered ?
(A) Speed of the machine
(B) Contact pressure
(C) Surface conditions of brush and commutator
(D) Excessive sparking
(e) All of the above
Ans: (e) All of the above

17. Carbon bearings are used under which of the following conditions ?
(A) Where lubrication is difficult or im-possible
(B) Where corrosive chemical action exists
(C) Where high temperature exists
(D) All of the above
Ans: (D) All of the above

18. Which of the following high resistance materials has the highest operating temperature ?
(A) Kanthal
(B) Manganin
(C) Nichrome
(D) Eureka
Ans: (A) Kanthal

19. is viscoelastic.
(A) Cast-iron
(6) Graphite
(C) Rubber
(D) Glass
Ans: (C) Rubber

20. Carbon electrodes are not used in
(A) GLS lamps
(B) electric arc furnace
(C) dry cells
(D) cinema projectors
Ans: (A) GLS lamps