MCQOPTIONS
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MCQOPTIONS
This section includes 286 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering materials knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following are the properties of ferromagnetic domains? |
| A. | 1 and 3 |
| B. | 2 and 4 |
| C. | 1, 3 and 4 |
| D. | 3 and 4 |
| Answer» D. 3 and 4 | |
| 52. |
When certain percentage of silicon is added to iron, the resistivity of the iron increase by a factor of 5. If a transformer core is made out of this iron, as compared to the previous value when silicon was not added, the eddy current loss will be: |
| A. | 77% |
| B. | 80% |
| C. | 83% |
| D. | 86% |
| Answer» C. 83% | |
| 53. |
Piezoelectric quartz crystal resonators find application where: |
| A. | signal amplification is required |
| B. | rectification of the signal is required |
| C. | signal frequency control is required |
| D. | modulation of signal is required |
| Answer» D. modulation of signal is required | |
| 54. |
The temperature coefficient of resistance for a thermistor is: |
| A. | low and negative |
| B. | low and positive |
| C. | high and negative |
| D. | high and positive |
| Answer» D. high and positive | |
| 55. |
Most commonly used N type impurity doping material is: |
| A. | Boron |
| B. | Phosphorous |
| C. | Arsenic/Antimony |
| D. | Silicon |
| Answer» D. Silicon | |
| 56. |
Ferromagnetic materials when heated to temperatures above. Curie temperature: |
| A. | behave as paramagnetic materials |
| B. | become ferrites |
| C. | tend towards superconductivity |
| D. | become insulators for heat and electricity |
| Answer» B. become ferrites | |
| 57. |
Piezoelectric is: |
| A. | material which becomes polarised when stressed |
| B. | a material which changes dimensions due to applied field |
| C. | a material that has properties midway between those of magnetic and non magnetic materials |
| D. | a material in which magnetising force reduces when current flowing is increased |
| Answer» B. a material which changes dimensions due to applied field | |
| 58. |
Which of the following is harder than diamond? |
| A. | Tantalum carbide |
| B. | Alumina ceramics |
| C. | Polycrystalline glass |
| D. | None of these |
| Answer» E. | |
| 59. |
Presence of sulphur in cast iron: |
| A. | promotes formation of graphite |
| B. | reduces fluidity during melting |
| C. | increases strength |
| D. | reduces oxidation |
| Answer» C. increases strength | |
| 60. |
In steel as the percentage of carbon increases which of the following decreases? |
| A. | Ultimate strength |
| B. | Hardness |
| C. | Ductility |
| D. | Parcentage of pearlite |
| Answer» D. Parcentage of pearlite | |
| 61. |
Which alloy of aluminium is often used for aeroplane and automobile parts? |
| A. | Duralumin |
| B. | Magnalium |
| C. | RR 53 |
| D. | Aluminium bronze |
| Answer» B. Magnalium | |
| 62. |
Which of the following is closest to the purest form of iron? |
| A. | Low carbon steel |
| B. | Cast iron |
| C. | Wrought iron |
| D. | Mild steel |
| Answer» D. Mild steel | |
| 63. |
What are the constituents of Phosphor bronze? |
| A. | Nickel, copper and cobalt |
| B. | Copper, zinc and manganese |
| C. | Copper, tin and phosphorous |
| D. | Aluminium, copper and nickel |
| Answer» D. Aluminium, copper and nickel | |
| 64. |
Dextrine is: |
| A. | a rubber based adhesive |
| B. | a starch glue |
| C. | a resin |
| D. | a paint |
| Answer» B. a starch glue | |
| 65. |
Which of the following statements is true of the critical temperature of a pure substance? |
| A. | The critical temperature is the temperature above which the liquid phase of a pure substance can exist |
| B. | The critical temperature is the temperature above which the liquid phase of a pure substance cannot exist |
| C. | The critical temperature is the temperature below which the liquid phase of a pure substance cannot exist |
| D. | The critical temperature is the temperature at which all three phases can coexist |
| Answer» C. The critical temperature is the temperature below which the liquid phase of a pure substance cannot exist | |
| 66. |
Semiconductor diode time constant is equal to: |
| A. | the value of majority carrier life time |
| B. | the life time of minority carrier |
| C. | the diffusion capacitance time constant |
| D. | zero |
| Answer» C. the diffusion capacitance time constant | |
| 67. |
A characteristic of the structure of metallic atoms is that: |
| A. | they tend to share their electrons with other atoms |
| B. | their atoms are smaller and more compact than those of nonmetallic elements |
| C. | their outermost orbital of electrons is nearly complete, and they attract electrons from other atoms |
| D. | the small number of electrons in their outermost orbital are weakly held and easily lost |
| Answer» E. | |
| 68. |
When a p-type semiconductor material is bonded to an ntype semiconductor material and terminals are added, the resulting structure does not have the property that: |
| A. | ideally, the forward bias resistance is zero |
| B. | as temperature is increased above room temperature, the material resistance decreases because the doping material charges are freed |
| C. | both holes and electrons contribute to the current flows |
| D. | the resistance increases with increasing doping |
| Answer» E. | |
| 69. |
Sodium alumino gels are also known as: |
| A. | borosilicate glass |
| B. | zeolites |
| C. | extrinsic semiconductors |
| D. | elastomers |
| Answer» C. extrinsic semiconductors | |
| 70. |
Which glass is resistant to heat and chemicals? |
| A. | Soda lime glass |
| B. | Silica glass |
| C. | Boro silicate glass |
| D. | Ceramic glass |
| Answer» D. Ceramic glass | |
| 71. |
Cobalt is: |
| A. | Ferromagnetic |
| B. | Ferroelectric |
| C. | Dielectric |
| D. | Paramagnetic |
| Answer» B. Ferroelectric | |
| 72. |
The Wiedemann-Franz law states that the ratio of thermal conductivity to electrical conductivity for a material is approximately constant, independent of the material for a fixed temperature. Moreover, as temperature changes, the ratio of thermal conductivity to electrical conductivity for a material is directly proportional to the temperature of the material. Which of the following is true of the Wiedemann-Franz law? |
| A. | (i) only |
| B. | (ii) only |
| C. | (ii) and (iii) |
| D. | (i), (ii), (iii) and (iv) |
| Answer» D. (i), (ii), (iii) and (iv) | |
| 73. |
Metal with hexagonal close packed structure is: |
| A. | Silver |
| B. | Iron |
| C. | Magnesium |
| D. | Aluminium |
| Answer» D. Aluminium | |
| 74. |
Scintillation is: |
| A. | change in dielectric constant of substances with change in humidity |
| B. | production of flashes of light by some substances when struck by alpha, beta or gamma rays |
| C. | deionisation of gases under low pressures |
| D. | variation of physical dimensions under the influence of magnetic field |
| Answer» D. variation of physical dimensions under the influence of magnetic field | |
| 75. |
Which of the following alloy has equal percentage of constituents? |
| A. | Constantan |
| B. | Duralumin |
| C. | Gunmetal |
| D. | White metal |
| Answer» B. Duralumin | |
| 76. |
German silver contains: |
| A. | 12.5% silver |
| B. | 5% silver |
| C. | 1% silver |
| D. | No silver |
| Answer» E. | |
| 77. |
Miller indices of plane ABC are: |
| A. | 121 |
| B. | 101 |
| C. | 111 |
| D. | 010 |
| Answer» D. 010 | |
| 78. |
When a p-type semiconductor material is bonded to an ntype semiconductor material and terminals are added the resulting structure has the property that: |
| A. | a built in potential results |
| B. | a voltage appears at the terminals |
| C. | resistance increases with increasing temperature |
| D. | a good conductor results since both n and p materials are doped |
| Answer» B. a voltage appears at the terminals | |
| 79. |
A silica tetrahedron is |
| A. | formed by four oxygen ions with their centres at the vertices of a tetrahedron and a silicon ion at the interstitial site inside the oxygen array |
| B. | a four sided figure (actually a square) arrangement of silicon ions, with one oxygen at the centre of the square |
| C. | the basic building block of all crystalline and glassy forms silica |
| D. | both (a) and (c) |
| Answer» E. | |
| 80. |
The model of the nucleus that best describes the process of fission is: |
| A. | liquid drop model |
| B. | cloudy crystal ball model |
| C. | optical model |
| D. | collective model |
| Answer» B. cloudy crystal ball model | |
| 81. |
In a transistor region is lightly doped and region is heavily doped. |
| A. | Base, emitter |
| B. | Collector, base |
| C. | Emitter, collector |
| D. | Emitter, base |
| Answer» B. Collector, base | |
| 82. |
A semiconductor is damaged by a strong current, because: |
| A. | Excess of electrons |
| B. | Decrease in electrons |
| C. | Lack of free electrons |
| D. | None of these |
| Answer» B. Decrease in electrons | |
| 83. |
A semiconductor X is made by doping germanium crystal with arsenic (Z = 33). Second semiconductor Y is made by doping germanium with indium (Z = 49). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct? |
| A. | X is p-type, Y is n-type and the junction is forward biased |
| B. | X is n-type, Y is n-type and the junction is forward biased |
| C. | X is p-type, Y is n-type and the junction is reverse biased |
| D. | X is n-type, Y is p-type and the junction is reverse biased |
| Answer» E. | |
| 84. |
If the frequency of light falling on a metal plate is doubled, the kinetic energy of emitted electrons will be: |
| A. | Exactly double |
| B. | Sightly more than double |
| C. | Slightly less than double |
| D. | Four times |
| Answer» D. Four times | |
| 85. |
The area enclosed by a hysteresis loop is a measure of: |
| A. | Relativity |
| B. | Susceptibility |
| C. | Permeability |
| D. | Energy loss per cycle |
| Answer» E. | |
| 86. |
Out of dia, para, and ferromagnetism which is the universal property of all substance is: |
| A. | Diamagnetism |
| B. | Paramagnetism |
| C. | Ferromagnetism |
| D. | All of these |
| Answer» B. Paramagnetism | |
| 87. |
Amplification of ultrasonic waves is possible in a piezoelectric semiconductor under applied electric field. The basic phenomenon involved is known as: |
| A. | Electrostriction |
| B. | Acousto-optic interaction |
| C. | Acousto-electric interaction |
| D. | Stimulated Brillouin scattering |
| Answer» B. Acousto-optic interaction | |
| 88. |
The relative permeability of a diamagnetic material is: |
| A. | Zero |
| B. | Equal to unity |
| C. | Less than unity |
| D. | More than unity |
| Answer» D. More than unity | |
| 89. |
Some ceramic superconductors become superconducting: |
| A. | below liquid helium temperature |
| B. | between liquid helium and liquid nitrogen temperatures |
| C. | above liquid nitrogen temperature but below room temperature |
| D. | above room temperature |
| Answer» C. above liquid nitrogen temperature but below room temperature | |
| 90. |
Consider the following materials: |
| A. | 1, 4, 3, 2 |
| B. | 1, 4, 2, 3 |
| C. | 4, 1, 3, 2 |
| D. | 4, 1, 2, 3 |
| Answer» C. 4, 1, 3, 2 | |
| 91. |
The relative dielectric constant of barium titanate at 100 C is about: |
| A. | 1 |
| B. | 5 |
| C. | 50 |
| D. | 2000 |
| Answer» E. | |
| 92. |
Magnetic permeability is maximum for: |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | None of these |
| Answer» D. None of these | |
| 93. |
In a piezoelectric crystal, application of a mechanical stress would produce: |
| A. | plastic deformation of the crystal |
| B. | magnetic dipoles in the crystal |
| C. | electrical polarization in the crystal |
| D. | shift in the Fermi level |
| Answer» D. shift in the Fermi level | |
| 94. |
Wire-wound resistance are used only when: |
| A. | precision is essential |
| B. | low values are required |
| C. | high power rating is necessary |
| D. | costly equipments are manufactured |
| Answer» D. costly equipments are manufactured | |
| 95. |
Which of the following elements act as donor impurities? |
| A. | 1, 2 and 3 |
| B. | 1, 2, 4 and 6 |
| C. | 3, 4, 5 and 6 |
| D. | 2, 4 and 5 |
| Answer» E. | |
| 96. |
Consider the following functions: |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 3 and 4 |
| D. | 1 and 4 |
| Answer» B. 2 and 3 | |
| 97. |
Which one of the following classes of materials can be categorised as ferrites? |
| A. | Plastics |
| B. | Metals |
| C. | Alloys |
| D. | Ceramics |
| Answer» E. | |
| 98. |
GaAs has an energy gap of 1.43 eV. The optical cut-off wavelength of GaAs would lie in the: |
| A. | visible region of the spectrum |
| B. | infrared region of the spectrum |
| C. | ultraviolet region of the spectrum |
| D. | far ultraviolet region of the spectrum |
| Answer» C. ultraviolet region of the spectrum | |
| 99. |
The hysteresis loop of a magnetic material has an area of 5 cm |
| A. | 15 W |
| B. | 20 W |
| C. | 25 W |
| D. | 50 W |
| Answer» D. 50 W | |
| 100. |
In superconducting state: |
| A. | entropy increases and thermal conductivity decreases |
| B. | entropy and thermal conductivity decreases |
| C. | entropy and thermal conductivity increases |
| D. | entropy decreases and thermal conductivity increases |
| Answer» C. entropy and thermal conductivity increases | |