Multiple Choice Questions (MCQ) on Electrical Engineering Materials for Electrical Engineering
1. The converse of hardness is known as
(a) malleability
(b) toughness
(c) softness
(d) none of the above
Ans: c
2. The tiny block formed by the arrangement of a small group of atoms is called the
(a) unit cell
(b) space lattice
(c) either (a) or (b)
(d) none of the above
Ans: a
3. The co-ordination number of a simple cubic structure is
(a) 2
(b) 4
(c) 6
(d) 8
Ans: c
4. The metal having the lowest temperature coefficient of resistance is
(a) gold
(b) copper
(c) aluminium
(d) kanthal
Ans: a
5. The kinetic energy of a bounded electron is
(a) less than that of unbounded electron
(b) greater than that of unbounded electron
(c) equal to that of unbounded electron
(d) infinite (e) none of the above
Ans: a
6. 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
7. 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
8. 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
9. The value of critical field below the transition temperature will
(a) increase
(b) decrease
(c) remain unchanged
(d) any of the above
Ans: a
10. 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
11. High resistivity materials are used in
(a) precision instruments
(b) heating elements
(c) motor starters
(d) incandescent lamps
(e) all of the above
Ans: e
12. Which of the following resistive materials has the lowest temperature co-efficient of resistance? (a) Nichrome
(b) Constantan
(c) Kanthal
(d) Molybdenum
Ans: a
13. The coils of D.C. motor starter are wound with wire of
(a) copper
(b) kanthal
(c) manganin
(d) nichrome
Ans: c
14. The transition temperature of mercury is
(a) 18.0°K
(b) 9.22°K
(c) 4.12°K
(d) 1.14’K
Ans: c
15. By increasing impurity content in the metal alloy the residual resistivity always
(a) decreases
(b) increases
(c) remains constant
(d) becomes temperature independent
Ans: b
16. At transition temperature the value of critical field is
(a) zero
(b) negative real value
(c) positive real value
(d) complex value
Ans: a
17. 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
18. Constantan contains
(a) silver and tin
(b) copper and tungsten
(c) tungsten and silver
(d) copper and nickel
Ans: d
19. Piezoelectric materials serve as a source of _____.
(a) resonant waves
(b) musical waves
(c) microwaves
(d) ultrasonic waves
Ans: d
20. In thermocouples which of the following pairs is commonly used?
(a) Copper-constantan
(b) Aluminium-tin
(c) Silver-German silver
(d) Iron-steel
Ans: a
21. Overhead telephone wires are made of
(a) aluminium
(b) steel
(c) ACSR conductors
(d) copper
Ans: b
22. Most of the common metals have _____ structure.
(a) linear
(b) hexagonal
(c) orthorhombic
(d) cubic
Ans: d
23. Which of the following affect greatly the resistivity of electrical conductors?
(a) Composition
(b) Pressure
(c) Size
(d) Temperature
Ans: a
24. _____ is a hard solder.
(a) Tin-lead
(b) Tin-silver-lead
(c) Copper-zinc
(d) None of the above
Ans: c
25. Non-linear resistors
(a) produce harmonic distortion
(b) follows Ohm’s law at low temperatures only
(c) result in non-uniform heating
(d) none of the above
Ans: a
26. In graphite, bonding is
(a) covalent
(b) metallic
(c) Vander Waals
(d) Vander Waals and covalent
Ans: d
27. Total number of crystal systems is
(a) 2
(b) 4
(c) 7
(d) 12
Ans: c
28. The conductivity of a metal is determined by
(a) the electronic concentration and the mobility of the free electrons
(b) the number of valence electrons per atom
(c) either (a) or (b)
(d) none of the above
Ans: a
29. The resistivity of a metal is a function of temperature because
(a) the amplitude of vibration of the atoms varies with temperature
(b) the electron density varies with temperature
(c) the electron gas density varies with temperature
Ans: a
30. 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 ft Any of the above
Ans: b
31. 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
32. Which of the following high resistance materials has the highest operating temperature?
(a) Kanthal
(b) Manganin
(c) Nichrome
(d) Eureka
Ans: a
33. Which of the following materials is used for making coils of standard resistances?
(a) Copper
(b) Nichrome
(c) Platinum
(d) Manganin
Ans: d
34. The conduction of electricity, in semiconductors, takes place due to movement of
(a) positive ions only
(b) negative ions only
(c) positive and negative ions
(d) electrons and holes
Ans: d
35. Selenium is _____ semiconductor.
(a) extrnisic
(b) intmisic
(c) N-type
(d) P-type
Ans: b
36. ________ has the best damping properties.
(a) Diamond
(b) High speed steel
(c) Mild steel
(d) Cast iron
Ans: d
37. The photo-electric effect occurs only when the incident light has more than a certain critical
(a) intensity
(b) speed
(c) frequency
(d) wave length
Ans: c
38. Superconducting metal in super conducting state has relative permeability of
(a) zero
(b) one
(c) negative
(d) more than one
Ans: a
39. The carbon percentage is least in
(a) low carbon steel
(b) wrought iron
(c) cast iron
(d) malleable iron
Ans: b
40. For a particular material, the Hall coefficient was found to be zero. The material is
(a) insulator
(b) metal
(c) intrinsic semiconductor
(d) none of the above
Ans: b
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