MCQOPTIONS
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MCQOPTIONS
This section includes 614 Mcqs, each offering curated multiple-choice questions to sharpen your GATE (Mechanical Engineering) knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
The metal having the lowest temperature coefficient of resistance is |
| A. | Gold |
| B. | Copper |
| C. | Aluminium |
| D. | Kanthal |
| Answer» B. Copper | |
| 402. |
The current due to electron flow in conduction band is the hole current in valence band. |
| A. | Equal to |
| B. | Less than |
| C. | Greater than |
| D. | Any of the above |
| Answer» D. Any of the above | |
| 403. |
Carbon resistors are used extensively because they are |
| A. | Easy to make |
| B. | Compact |
| C. | Inexpensive |
| D. | All of the above reasons |
| Answer» E. | |
| 404. |
Which of the following affect greatly the resistivity of electrical conductors? |
| A. | Composition |
| B. | Pressure |
| C. | Size |
| D. | Temperature |
| Answer» B. Pressure | |
| 405. |
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. | All of the above |
| Answer» E. | |
| 406. |
The coils of D.C. motor starter are wound with wire of |
| A. | Copper |
| B. | Kanthal |
| C. | Manganin |
| D. | Nichrome |
| Answer» D. Nichrome | |
| 407. |
Is an element used in semiconductors whose atoms have three valence electrons. |
| A. | An acceptor |
| B. | A donor |
| C. | Germanium |
| D. | Silicon |
| Answer» B. A donor | |
| 408. |
A highly conductive material must have |
| A. | Highest conductivity |
| B. | Lowest temperature co-efficient |
| C. | Good mechanical strength |
| D. | Good corrosion resistance |
| E. | All of the above |
| Answer» F. | |
| 409. |
In conductors conduction of electricity takes place due to movement of |
| A. | Electrons only |
| B. | Positive ions only |
| C. | Negative ions only |
| D. | Positive and negative ions |
| Answer» B. Positive ions only | |
| 410. |
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 |
| Answer» E. | |
| 411. |
The co-ordination number of a simple cubic structure is |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» D. 8 | |
| 412. |
In a superconductor the value of critical density depends upon |
| A. | Magnetic field strength |
| B. | Temperature |
| C. | Either A or B |
| D. | Both A and B |
| Answer» E. | |
| 413. |
__________ is the main constituent of glass |
| A. | Fe203 |
| B. | Si02 |
| C. | AI2O3 |
| D. | B2O3 |
| Answer» C. AI2O3 | |
| 414. |
Constantan contains |
| A. | Silver and tin |
| B. | Copper and tungsten |
| C. | Tungsten and silver |
| D. | Copper and nickel |
| Answer» E. | |
| 415. |
Which of the following is a semiconductor material ? |
| A. | Phosphorous |
| B. | Rubber |
| C. | Silicon |
| D. | Aluminium |
| Answer» D. Aluminium | |
| 416. |
_______ has zero temperature co-efficient of resistance. |
| A. | Aluminium |
| B. | Carbon |
| C. | Porcelain |
| D. | Manganin |
| Answer» E. | |
| 417. |
Copper, even though costly, finds use in the windings of electrical machines because |
| A. | Copper points offer low contact resistance |
| B. | Copper can be easily soldered and welded |
| C. | Copper windings are less bulky and the machines become compact |
| D. | All of the above |
| Answer» E. | |
| 418. |
Thermonic emission occurs in |
| A. | Vacuum tubes |
| B. | Copper conductors |
| C. | Ferrite cores |
| D. | Transistors |
| Answer» B. Copper conductors | |
| 419. |
For germanium the forbidden energy gap is |
| A. | 0.15 eV |
| B. | 0.25 eV |
| C. | 0.5eV |
| D. | 0.7eV |
| Answer» E. | |
| 420. |
Which of the following materials does not have covalent bonds ? |
| A. | Organic polymers |
| B. | Silicon |
| C. | Metals |
| D. | |
| Answer» D. | |
| 421. |
Most of the common metals have _________ structure. |
| A. | Linear |
| B. | Hexagonal |
| C. | Orthorhombic |
| D. | Cubic |
| Answer» E. | |
| 422. |
Low resistivity materials are used in |
| A. | Transformer, motor and generator windings |
| B. | Transmission and distribution lines |
| C. | House wiring |
| D. | All above applications |
| Answer» E. | |
| 423. |
High resistivity materials are used in |
| A. | Precision instruments |
| B. | Heating elements |
| C. | Motor starters |
| D. | Incandescent lamps |
| E. | All of the above |
| Answer» F. | |
| 424. |
The minority carrier concentration is largely a function of |
| A. | Forward biasing voltage |
| B. | Reverse biasing voltage |
| C. | Temperature |
| D. | The amount of doping |
| Answer» D. The amount of doping | |
| 425. |
Which of the following materials is used for making coils of standard resistances ? |
| A. | Copper |
| B. | Nichrome |
| C. | Platinum |
| D. | Manganin |
| Answer» E. | |
| 426. |
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 | |
| 427. |
Spark plug makes use of which of the following materials for insulation ? |
| A. | Porcelain |
| B. | Slate |
| C. | Asbestos |
| D. | Glass |
| Answer» B. Slate | |
| 428. |
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 | |
| 429. |
Selenium is _____ semiconductor. |
| A. | Extrnisic |
| B. | Intmisic |
| C. | N-type |
| D. | P-type |
| Answer» C. N-type | |
| 430. |
_______ 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 | |
| 431. |
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 |
| D. | None of the above |
| Answer» B. The electron density varies with temperature | |
| 432. |
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 | |
| 433. |
_______ is an example of piezoelectric material. |
| A. | Glass |
| B. | Quartz |
| C. | Corrundum |
| D. | Neoprene |
| Answer» C. Corrundum | |
| 434. |
Is the property of absorbing moisture from atmosphere. |
| A. | Solubility |
| B. | Viscosity |
| C. | Porosity |
| D. | Hygroscopicity |
| Answer» E. | |
| 435. |
Commonly used conducting materials are |
| A. | Copper |
| B. | Aluminium |
| C. | Both A and B |
| D. | Copper and silver |
| E. | Platinum and gold |
| Answer» D. Copper and silver | |
| 436. |
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 |
| Answer» E. | |
| 437. |
The conductivity of an extrinsic semiconductor with temperature |
| A. | Decreases |
| B. | Increases |
| C. | Remains constant |
| D. | All of the above |
| Answer» D. All of the above | |
| 438. |
Which of the following materials is the best conductor of electricity ? |
| A. | Tungsten |
| B. | Aluminium |
| C. | Copper |
| D. | Carbon |
| Answer» D. Carbon | |
| 439. |
Which of the following is the poorest conductor of electricity ? |
| A. | Carbon |
| B. | Steel |
| C. | Silver |
| D. | Aluminium |
| Answer» B. Steel | |
| 440. |
Superconducting metal in super conducting state has relative permeability of |
| A. | Zero |
| B. | One |
| C. | Negative |
| D. | More than one |
| Answer» B. One | |
| 441. |
Effect of moisture on the insulating materials is to |
| A. | Decrease dielectric constant |
| B. | Decrease dielectric strength |
| C. | Decrease insulation resistance |
| D. | Increase dielectric loss |
| E. | All of the above |
| Answer» F. | |
| 442. |
________ has the best damping properties. |
| A. | Diamond |
| B. | High speed steel |
| C. | Mild steel |
| D. | Cast iron |
| Answer» E. | |
| 443. |
Mercury as an electric contact material is |
| A. | A liquid |
| B. | A metal |
| C. | A metal liquid |
| D. | A gas |
| Answer» D. A gas | |
| 444. |
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 |
| Answer» B. Increasing its temperature | |
| 445. |
Super conductivity can be destroyed by |
| A. | Adding impurities |
| B. | Reducing temperatures |
| C. | Application of magnetic field |
| D. | Any of the above |
| Answer» D. Any of the above | |
| 446. |
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 |
| Answer» B. Greater than that of unbounded electron | |
| 447. |
Steel wire is used as |
| A. | Overhead telephone wire |
| B. | Earth wire |
| C. | Core wire of ACSR |
| D. | All of the above |
| Answer» E. | |
| 448. |
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 |
| Answer» B. The number of valence electrons per atom | |
| 449. |
Which of the following is an advantage of stranded conductor over equivalent single conductor ? |
| A. | Less liability to kink |
| B. | Greater flexibility |
| C. | Less liability to break |
| D. | All of the above |
| Answer» E. | |
| 450. |
Due to which of the following fact, in India, aluminium is replacing copper ? |
| A. | Aluminium is more ductile and malleable than copper |
| B. | Aluminium is available in plenty, cheaper and lighter than copper |
| C. | Aluminium has lower resistivity than that of copper |
| D. | Aluminium has less temperature co-efficient than copper |
| Answer» C. Aluminium has lower resistivity than that of copper | |