MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The number of atoms per unit cell in B.C.C. structure is |
| A. | 1 |
| B. | 2 |
| C. | 4 |
| D. | 8 |
| Answer» C. 4 | |
| 2. |
Total number of crystal systems is |
| A. | 2 |
| B. | 4 |
| C. | 7 |
| D. | 12 |
| Answer» D. 12 | |
| 3. |
In graphite, bonding is |
| A. | covalent |
| B. | metallic |
| C. | Vander Waals |
| D. | Vander Waals and covalent |
| Answer» E. | |
| 4. |
Which of the following materials does not have covalent bonds ? |
| A. | Organic polymers |
| B. | Metals |
| Answer» C. | |
| 5. |
A carbon resistor contains |
| A. | carbon crystals |
| B. | solid carbon granules |
| C. | pulverized coal |
| D. | finely divided carbon black. |
| Answer» E. | |
| 6. |
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 |
| Answer» B. follows Ohm’s law at low temperatures only | |
| 7. |
Addition of 0.3 to 4.5% silicon to iron _____ the electrical resistivity of iron. |
| A. | increases |
| B. | decreases |
| Answer» B. decreases | |
| 8. |
Underground cables are laid at sufficient depth |
| A. | to minimise temperature stresses |
| B. | to avoid being unearthed easily due to removal of soil |
| C. | to minimise the effect of shocks and vibrations due to gassing vehicles, etc |
| D. | for all of the above reasons |
| Answer» D. for all of the above reasons | |
| 9. |
_____ is a hard solder. |
| A. | Tin-lead |
| B. | Tin-silver-lead |
| C. | Copper-zinc |
| D. | None of the above |
| Answer» D. None of the above | |
| 10. |
Thermonic emission occurs in |
| A. | vacuum tubes |
| B. | copper conductors |
| C. | ferrite cores |
| D. | transistors |
| Answer» B. copper conductors | |
| 11. |
Which of the following affect greatly the resistivity of electrical conductors ? |
| A. | Composition |
| B. | Pressure |
| C. | Size |
| D. | Temperature |
| Answer» B. Pressure | |
| 12. |
Most of the common metals have _____ structure |
| A. | linear |
| B. | hexagonal |
| C. | orthorhombic |
| D. | cubic |
| Answer» E. | |
| 13. |
A good electric contact material should have all of the following properties except |
| A. | high resistivity |
| B. | high resistivity |
| C. | good thermal conductivity |
| D. | high melting point |
| Answer» B. high resistivity | |
| 14. |
_____ is the main constituent of glass |
| A. | Fe203 |
| B. | Si02 |
| C. | AI2O3 |
| D. | B2O3 |
| Answer» C. AI2O3 | |
| 15. |
______ is an example of piezoelectric material. |
| A. | Glass |
| B. | Quartz |
| C. | Corrundum |
| D. | Neoprene |
| Answer» C. Corrundum | |
| 16. |
Overhead telephone wires are made of |
| A. | aluminium |
| B. | steel |
| C. | ACSR conductors |
| D. | copper |
| Answer» C. ACSR conductors | |
| 17. |
Capacitance grading of cable implies |
| A. | use of dielectrics of different permeabilities |
| B. | grading according to capacitance of cables per km length |
| C. | cables using single dielectric in different concentrations |
| D. | capacitance required to be introduced at different lengths to counter the effect of inductance |
| Answer» B. grading according to capacitance of cables per km length | |
| 18. |
______ is most commonly used for making magnetic recording tape |
| A. | Silver nitrate |
| B. | Ferric oxide |
| C. | Small particles of iron |
| D. | Silicon-iron |
| Answer» C. Small particles of iron | |
| 19. |
In a cable the voltage stress is maximum at |
| A. | sheath |
| B. | insulator |
| C. | surface of the conductor |
| D. | core of the conductor |
| Answer» E. | |
| 20. |
Solder is an alloy of |
| A. | copper and aluminium |
| B. | tin and lead |
| C. | nickel, copper and zinc |
| D. | silver, copper and lead |
| Answer» C. nickel, copper and zinc | |
| 21. |
Carbon electrodes are not used in |
| A. | GLS lamps |
| B. | electric arc furnace |
| C. | dry cells |
| D. | cinema projectors |
| Answer» B. electric arc furnace | |
| 22. |
A cable carrying alternating current has |
| A. | hysteresis losses only |
| B. | hysteresis and leakage losses only |
| C. | hysteresis, leakage and copper losses only |
| D. | hysteresis, leakage, copper and friction losses |
| Answer» C. hysteresis, leakage and copper losses only | |
| 23. |
The insulation of the cable decreases with |
| A. | the increase in length of the insulation |
| B. | the decrease in the length of the insulation |
| C. | either (a) or (b) |
| D. | none of the above |
| Answer» B. the decrease in the length of the insulation | |
| 24. |
The breakdown of insulation of the cable can be avoided economically by the use of |
| A. | inter-sheaths |
| B. | insulating materials with different dielectric constants |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 25. |
is viscoelastic. |
| A. | Cast-iron |
| B. | Graphite |
| C. | Rubber |
| D. | Glass |
| Answer» D. Glass | |
| 26. |
The electrostatic stress in underground cables is |
| A. | same at the conductor and the sheath |
| B. | minimum at the conductor and maximum at the sheath |
| C. | maximum at the conductor and minimum at the sheath |
| D. | zero at the conductor as well as on the sheath |
| Answer» D. zero at the conductor as well as on the sheath | |
| 27. |
In thermocouples which of the following pairs is commonly used ? |
| A. | Copper-constantan |
| B. | Aluminium-tin |
| C. | Silver-German silver |
| D. | Iron-steel |
| Answer» B. Aluminium-tin | |
| 28. |
The intersheaths in the cables are used to |
| A. | minimize the stress |
| B. | avoid the requirement of good insulation |
| C. | provide proper stress distribution |
| D. | none of the above |
| Answer» D. none of the above | |
| 29. |
Piezoelectric materials serve as a source of _____ . |
| A. | resonant waves |
| B. | musical waves |
| C. | microwaves |
| D. | ultrasonic waves |
| Answer» E. | |
| 30. |
______ has zero temperature co-efficient of resistance. |
| A. | Aluminium |
| B. | Carbon |
| C. | Porcelain |
| D. | Manganin |
| Answer» E. | |
| 31. |
In the cables, sheaths are used to |
| A. | prevent the moisture from entering the cable |
| B. | provide enough strength |
| C. | provide proper insulation |
| D. | none of the above |
| Answer» B. provide enough strength | |
| 32. |
Which of the following is the poorest conductor of electricity ? |
| A. | Carbon |
| B. | Steel |
| C. | Silver |
| D. | Aluminium |
| Answer» B. Steel | |
| 33. |
Constantan contains |
| A. | silver and tin |
| B. | copper and tungsten |
| C. | tungsten and silver |
| D. | copper and nickel |
| Answer» E. | |
| 34. |
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 |
| Answer» D. Copper containing traces of silicon | |
| 35. |
At transition temperature the value of critical field is |
| A. | zero |
| B. | negative real value |
| C. | positive real value |
| D. | complex value |
| Answer» B. negative real value | |
| 36. |
If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be |
| A. | 5 kV/mm |
| B. | 10 kV/mm |
| C. | 15 kV/mm |
| D. | 30 kV/mm |
| Answer» C. 15 kV/mm | |
| 37. |
A certain cable has an insulation of relative permittivity 4. If the insulation is replaced by one of relative permittivity 2, the capacitance of the cable will become |
| A. | one half |
| B. | double |
| C. | four times |
| D. | none of the above |
| Answer» B. double | |
| 38. |
In cables the charging current |
| A. | lags the voltage by 90° |
| B. | leads the voltage by 90° |
| C. | lags the voltage by 180° |
| D. | leads the voltage by 180° |
| Answer» C. lags the voltage by 180° | |
| 39. |
The structure sensitive property of a super conductor is |
| A. | critical magnetic field |
| B. | transition temperature |
| C. | critical current density |
| D. | none of the above |
| Answer» D. none of the above | |
| 40. |
By increasing impurity content in the metal alloy the residual resistivity always |
| A. | decreases |
| B. | increases |
| C. | remains constant |
| D. | becomes temperature independent |
| Answer» C. remains constant | |
| 41. |
If the length of a cable is doubled, its capacitance |
| A. | becomes one-fourth |
| B. | becomes one-half |
| C. | becomes double |
| D. | remains unchanged |
| Answer» D. remains unchanged | |
| 42. |
The transition temperature of mercury is |
| A. | 18.0°K |
| B. | 9.22°K |
| C. | 4.12°K |
| D. | 1.14’K |
| Answer» D. 1.14’K | |
| 43. |
Solid type cables are considered unreliable beyond 66 kV because |
| A. | insulation may melt due to higher temperature |
| B. | skin effect dominates on the conductor |
| C. | of corona loss between conductor and sheath material |
| D. | there is a danger of breakdown of insulation due to the presence of voids |
| Answer» E. | |
| 44. |
The conductors have transport phenomena of electrons due to |
| A. | electric field |
| B. | magnetic field |
| C. | electromagnetic field |
| D. | none of the above |
| Answer» B. magnetic field | |
| 45. |
The coils of D.C. motor starter are wound with wire of |
| A. | copper |
| B. | kanthal |
| C. | manganin |
| D. | nichrome |
| Answer» D. nichrome | |
| 46. |
The relative permittivity of rubber is |
| A. | between 2 and 3 |
| B. | between 5 and 6 |
| C. | between 8 and 10 |
| D. | between 12 and 14 |
| Answer» B. between 5 and 6 | |
| 47. |
Which of the following resistive materials has the lowest temperature co-efficient of resistance ? |
| A. | Nichrome |
| B. | Constantan |
| C. | Kanthal |
| D. | Molybdenum |
| Answer» B. Constantan | |
| 48. |
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 |
| Answer» B. a wire of platinum | |
| 49. |
Cables, generally used beyond 66 kV are |
| A. | oil filled |
| B. | S.L. type |
| C. | belted |
| D. | armoured |
| Answer» B. S.L. type | |
| 50. |
Mercury as an electric contact material is |
| A. | a liquid |
| B. | a metal |
| C. | a metal liquid |
| D. | a gas |
| Answer» D. a gas | |