Electrical Engineering Materials Multiple Choice Questions and Answers-2 (English)

1. Solder is an alloy of
(A) copper and aluminium
(B) tin and lead
(C) nickel, copper and zinc
(D) silver, copper and lead
Ans: (B) tin and lead

2 ______ is most commonly used for making magnetic recording tape
(A) Silver nitrate
(B) Ferric oxide
(C) Small particles of iron
(D) Silicon-iron
Ans: (B) Ferric oxide

3. Overhead telephone wires are made of
(A) aluminium
(B) steel
(C) ACSR conductors
(D) copper
Ans: (B) steel

4. Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
(A) Nichrome
(B) Constantan
(C) Kanthal
(D) Molybdenum
Ans: (A) Nichrome

5. The coils of D.C. motor starter are wound with wire of
(A) copper
(B) kanthal
(C) manganin
(D) nichrome
Ans: (C) manganin

6. The kinetic energy of a bounded electron is
(A) less than that of unbounded electron
(6) greater than that of unbounded electron
(C) equal to that of unbounded electron
(D) infinite
(e) none of the above
Ans: (A) less than that of unbounded electron

7. A highly conductive material must have
(A) highest conductivity
(B) lowest temperature co-efficient
(C) good mechanical strength
(D) good corrosion resistance
(e) easy solderable and drawable quality
(f) all of the above
Ans: (f) all of the above

8. 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
Ans: (A) decreasing its temperature

9. Superconductivity is observed for
(A) infrared frequencies
(B) d.c. and low frequency
(C) a.c. and high frequency
(D) frequencies having no effect
(e) none of the above
Ans: (B) d.c. and low frequency

10. The superconductivity is due to
(A) the crystal structure having no atomic vibration at 0°K
(B) all electrons interact in the super-conducting state
(C) the electrons jump into nucleus at 0°K
(D) none of the above
Ans: (A) the crystal structure having no atomic vibration at 0°K

11. Superconductors are becoming popular for use in
(A) generating very strong magnetic field
(B) manufacture of bubble memories
(C) generating electrostatic field
(D) generating regions free from magnetic field
Ans: (A) generating very strong magnetic field

12. High resistivity materials are used in
(A) precision instruments
(6) heating elements
(C) motor starters
(D) incandescent lamps
(e) all of the above
Ans: (e) all of the above

13. Mercury as an electric contact material is
(A) a liquid
(B) a metal
(C) a metal liquid
(D) a gas
Ans: (C) a metal liquid

14. An H.R.C. fuse is
(A) a ceramic body having metal and caps
(B) a wire of platinum
(C) a heavy cross-section of copper or aluminium
(D) a ceramic tube having carbon rod inside it
Ans: (A) a ceramic body having metal and caps

15. Which of the following variety of copper has the best conductivity ?
(A) Induction hardened copper
(B) Hard drawn copper
(C) Pure annealed copper
(D) Copper containing traces of silicon
Ans: (C) Pure annealed copper

16. Constantan contains
(A) silver and tin
(B) copper and tungsten
(C) tungsten and silver
(D) copper and nickel
Ans: (D) copper and nickel

17. Which of the following is the poorest conductor of electricity ?
(A) Carbon
(B) Steel
(C) Silver
(D) Aluminium
Ans: (A) Carbon

18 ______ has zero temperature co-efficient of resistance.
(A) Aluminium
(B) Carbon
(C) Porcelain
(D) Manganin
Ans: (D) Manganin

19. At transition temperature the value of critical field is
(A) zero
(B) negative real value
(C) positive real value
(D) complex value
Ans: (A) zero

20. Piezoelectric materials serve as a source of _____ .
(A) resonant waves
(B) musical waves
(C) microwaves
(D) ultrasonic waves
Ans: (D) ultrasonic waves