McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 351. |
Optic fibres are used in : |
| A. | CAT scans |
| B. | X-ray photos |
| C. | Ultrasound scans |
| D. | Endoscopy |
| Answer» D. Endoscopy | |
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Explanation: Optical fibres are used in endoscopic instruments that enable doctors to view internal body parts without having to perform surgery. Fernando Alves Martins of Portugal invented the first fiber optic endoscope in 1963-64. Further innovations included using additional fibres to channel light to the objective end from a powerful external source, thereby achieving the high level of full spectrum illumination that was needed for detailed viewing, and colour photography. |
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| 352. |
Two waves, each of amplitude 1.5 mm and frequency 10 Hz, are travelling in opposite direction with a speed of 20 mm/s. The distance in mm between adjacent nodes is : |
| A. | 1.0 |
| B. | 1.2 |
| C. | 1.5 |
| D. | 2.0 |
| Answer» A. 1.0 | |
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Explanation: Since the amplitudes, frequency and the speed of both the waves are in same, hence the wavelength of the composite wave will be the same as the single wave. |
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| 353. |
While catching a ball, a player pulls down his hands to lower the – |
| A. | force |
| B. | momentum |
| C. | impulse |
| D. | catching time |
| Answer» B. momentum | |
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Explanation: A cricketer lowers his hands while taking a catch to decrease the rate of momentum. Cricketers increase the time by pulling their hand's backward with the ball while taking a catch. Linear momentum or translational momentum is the product of the mass and velocity of an object. For example, a heavy truck moving fast has a large momentum—it takes a large and prolonged force to get the truck up to this speed, and it takes a large and prolonged force to bring it to a stop afterwards. If the truck were lighter, or moving slower, then it would have less momentum. |
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| 354. |
A camera uses a to form an image on a piece of film at the back. |
| A. | convex lens |
| B. | concave lens |
| C. | diverging lens |
| D. | none of these |
| Answer» A. convex lens | |
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Explanation: A camera consists of three main parts. • The body which is light tight and contains all the mechanical parts. • The lens which is a convex lens. • The film or a charged couple device in the case of a digital camera. |
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| 355. |
In 1866, John Newlands, an English scientist, arranged the then known elements in the order of increasing atomic masses. He found that every eighth element had properties similar to that of the first. He called it the - |
| A. | Law of Pentamates |
| B. | Law of musical notes |
| C. | Law of Octaves |
| D. | None of the above |
| Answer» C. Law of Octaves | |
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Explanation: Newlands compared his discovery to the octaves found in music and thus, he called it the ‘Law of Octaves’. It is also known as ‘Newlands’ Law of Octaves’. |
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| 356. |
Which of the following pairs of physical quantities have the same dimensions? |
| A. | Force and Power |
| B. | Work and Power |
| C. | Work and Energy |
| D. | Momentum and Power |
| Answer» C. Work and Energy | |
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Explanation: The term energy is used to describe the capacity of a system to do work on another system. Energy of all types (Surface Tension, Kinetic, Potential etc.) have the same dimension and unit as that of Work. |
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| 357. |
Magnetism in materials is due to - |
| A. | electrons at rest |
| B. | circular motion of electrons |
| C. | protons at rest |
| D. | all neutrons at rest |
| Answer» B. circular motion of electrons | |
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Explanation: Myopia is commonly known shortsighted. It is a condition of the eye where the light that comes in does not directly focus on the retina but in front of it. This causes the image that one sees when looking at a distant object to be out of focus but in focus when looking at a close object. Eye care professionals most commonly correct myopia through the use ofcorrective lenses, such as glasses or contact lenses. |
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| 358. |
The outermost layer of the Sun is called |
| A. | chromosphere |
| B. | photosphere |
| C. | corona |
| D. | lithosphere |
| Answer» C. corona | |
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Explanation: Our Sun is surrounded by a blanket of gases called ‘an atmosphere'. The corona is the outermost part of the Sun’s atmosphere. |
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| 359. |
During washing of clothes, we use indigo due to its – |
| A. | Better cleaning action |
| B. | Proper pigmental composition |
| C. | High glorious nature |
| D. | Very low cost |
| Answer» B. Proper pigmental composition | |
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Explanation: Indigo is a dye different than any other. It does not require any mordant. Rather it is dyed through a living fermentation process. The process "reduces" the Indigo, changing it from blue to yellow. In this state, it dissolves in an alkaline solution. The fibre is worked in the solution, or "vat". When brought out to the air, it is a blight green. Slowly the ail-changes it to the beautiful deep and rich blue of Indigo. |
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| 360. |
Watt is a unit of - |
| A. | Time |
| B. | Power |
| C. | Light |
| D. | intensity of light |
| Answer» B. Power | |
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Explanation: 0 |
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| 361. |
Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in - |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Both conduction and convection |
| Answer» B. Convection | |
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Explanation: The process of heat transfer from one place to another place without the movement of particles is called conduction, |
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| 362. |
Water drops are spherical because of - |
| A. | viscosity |
| B. | density |
| C. | polarity |
| D. | surface tension |
| Answer» D. surface tension | |
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Explanation: Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually all liquids would be approximately spherical. |
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| 363. |
If the temperature of a piece increases suddenly, the relative humidity– |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | fluctuates |
| Answer» B. decreases | |
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Explanation: Relative humidity is the ratio of the partial pressure of water vapour in a air- water mixture to the saturated vapour pressure of water at a specific temperature. |
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| 364. |
What changes will happen to a bowl of ice and water kept at exactly zero degree Celsius? |
| A. | All ice will melt |
| B. | All water will become ice |
| C. | No change will happen |
| D. | Only some ice will melt |
| Answer» C. No change will happen | |
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Explanation: Fresh water cooled to zero (0) degree Celsius and subjected to additional lossof heat energy normally will freeze. A mixture of fresh water and ice has an equilibrium temperature of zero (0) degree Celsius. Adding heat to the mixture causes ice to melt whereas removing heat causes water to freeze. For that reason, 0 (zero) degree Celsius is called the freezing point of fresh water. Cloud droplets can cool well below the usual freezing point while remaining liquid. Such cloud droplets are composed of super cooled water. |
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| 365. |
Curie point is the temperature at which |
| A. | Matter becomes radioactive |
| B. | A metal loses magnetic properties |
| C. | A metal loses conductivity |
| D. | Transmutation of metal occurs |
| Answer» B. A metal loses magnetic properties | |
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Explanation: In physics and materials science, the Curie temperature (TO, or Curie point, is the temperature at which a ferromagnetic or a ferromagnetic material becomes paramagnetic on heating; the effect is reversible. A magnet will lose its magnetism if heated above the Curie temperature. The term is also used in piezoelectric materials to refer to the temperature at which spontaneous polarization is lost on heating. |
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| 366. |
Which of the following is true regarding Newland’s Law of Octaves? |
| A. | It worked well with only lighter elements. |
| B. | It was applicable only up to calcium. |
| C. | Both are correct |
| D. | Both are incorrect. |
| Answer» C. Both are correct | |
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Explanation: Both the statements are correct. Hence, option C is correct. |
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| 367. |
When a bottle of perfume is opened in one corner of a room the smell spreads soon throughout the room. This is an example of - |
| A. | surface tension |
| B. | capillarit |
| C. | viscosity |
| D. | diffusion |
| Answer» A. surface tension | |
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Explanation: Diffusion is the spreading – mixing of gases through molecular motion. |
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| 368. |
The material used in the fabrication of a transistor is – |
| A. | Aluminium |
| B. | Copper |
| C. | Silicon |
| D. | Silver |
| Answer» C. Silicon | |
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Explanation: A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. The first transistors were made from germanium (Ge). Silicon (Si) types currently predominate but certain advanced microwave and high performance versions now employ the compound semiconductor material gallium arsenide (GaAs) and the semiconductor alloy silicon germanium (SiGe). |
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| 369. |
If there is a circular hole in a metal plate, what happens to the radius of the hole when the plate is heated? |
| A. | Increases |
| B. | Decreases |
| C. | Unchanged |
| D. | Depends upon the metal |
| Answer» A. Increases | |
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Explanation: When a metal plate with a circular hole at its centre is heated, definitely along with the areal expansion of the plate the diameter of the circular hole also increases. Using the differential equations of coefficients of expansions, we find that the hole radius increases at the same linear rate as the metal. |
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| 370. |
The velocity of sound is more in – |
| A. | water |
| B. | air |
| C. | steel |
| D. | wood |
| Answer» C. steel | |
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Explanation: Sound travels at different speeds depending on what it is traveling through. Of the three mediums (gas, liquid, and solid) sound waves travel the slowest through gases, faster through liquids, and fastest through solids. They travel over 17 times faster through steel than through air. |
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| 371. |
Radio activity is due to – |
| A. | unstable nucleus |
| B. | stable nucleus |
| C. | stable electronic configuration |
| D. | stable electronic configuration |
| Answer» A. unstable nucleus | |
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Explanation: Radioactivity is caused by unstable nuclei trying to become stable by emitting particles and or energy. The nuclei of radioactive substances are unstable due to an unstable ratio of protons to neutrons. |
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| 372. |
Which conservation principle is applicable in the case of the motion of a rocket? |
| A. | Conservation of mass |
| B. | Conservation of charge |
| C. | Conservation of momentum |
| D. | Conservation of energy |
| Answer» C. Conservation of momentum | |
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Explanation: The motion of a rocket is an application of Newton's third law of motion and law of conservation of linear momentum. The operation of a rocket illustrates the conservation of momentum. Just before launching, the momentum of the rocket is zero. When the rocket is fired, it forces a jet of hot gases with a high velocity through the nozzle. |
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| 373. |
These waves cannot be trans-mitted through vacuum – |
| A. | Light |
| B. | Sound |
| C. | Heat |
| D. | Electromagnetic |
| Answer» B. Sound | |
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Explanation: Sound is a mechanical wave that is created by vibrating objects and propagated through a medium from one location to another. Because mechanical waves rely on particle interaction in order to transport their energy, they cannot travel through regions of space that are void of particles. That is, mechanical waves cannot travel through a vacuum. |
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| 374. |
A gap is left between two rails of a railway track to accommodate of the metal. |
| A. | areal expansion |
| B. | volume expansion |
| C. | liner expansion |
| D. | apparent expansion |
| Answer» C. liner expansion | |
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Explanation: The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. To a first approximation, the change in length measurements of an object ("linear dimension" as opposed to, e.g., volumetric dimension) due to thermal expansion is related to temperature change by a "linear expansion coefficient". It is the fractional change in length per degree of temperature change. |
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| 375. |
If an ordinary glass tube and a glass capillary tube are 'both clipped in a beaker of water, water rises in – |
| A. | both |
| B. | only the glass tube |
| C. | only the capillary tube |
| D. | neither |
| Answer» A. both | |
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Explanation: The rise or fall of liquid due to capillarity in a beaker of water depends upon the radius of the bore of the tube (s) which is/are dipped into it. The narrower the bore of the tube, the greater is the rise or fall of the liquid in the tube. So in this case, water will rise in both the glass tube and the glass capillary tube. |
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| 376. |
Optical fibres are based on the phenomenon of – |
| A. | Interference |
| B. | Dispersion |
| C. | Diffraction |
| D. | Total Internal Reflection |
| Answer» D. Total Internal Reflection | |
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Explanation: An optical fiber (or optical fibre) is a flexible, transparent fiber made of glass (Silica) or plastic, slightly thicker than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. Optical fibers typically include a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by total internal reflection. This causes the fiber to act as a waveguide. |
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| 377. |
Who was the inventor of frozen foods? |
| A. | Alfred Nobel |
| B. | Clarence Birdseye |
| C. | Frank Whittle |
| D. | Ives McGaffey |
| Answer» B. Clarence Birdseye | |
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Explanation: Clarence Birdseye, an American entrepreneur, and naturalist, is considered to be the founder of the modern frozen food industry. He invented the quick-freezing method in 1924, which produces the type of frozen foods that we know today. |
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| 378. |
The clouds float in the atmosphere because of their low: |
| A. | temperature |
| B. | velocity |
| C. | pressure |
| D. | density |
| Answer» D. density | |
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Explanation: Clouds generally form, survive and grow in air that is moving upward. Rising air expands as the pressure on it decreases, and that expansion into thinner, high-altitude air causes cooling. |
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| 379. |
A person is hurt on kicking a stone due to – |
| A. | Inertia |
| B. | Velocity |
| C. | Reaction |
| D. | Momentum |
| Answer» C. Reaction | |
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Explanation: Newton's third law states that "For every action, there is an equal and opposite reaction." The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. So harder the stone is kicked, the harder will be its effect on the hitter. |
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| 380. |
The fuse in our domestic electric circuit melts when there is a high rise in – |
| A. | Inductance |
| B. | Current |
| C. | Resistance |
| D. | Capacitance |
| Answer» B. Current | |
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Explanation: In electronics and electrical engineering, a fuse is a type of low resistance resistor that acts as a sacrificial device to provide over protection, of either the load or source circuit. It's essential component is a metal wire or strip that melts when too much current flows, which interrupts the circuit in which it is connected. Short circuit, overloading, mismatched loads or device failure are the prime reasons for excessive current. A fuse interrupts excessive current (blows) so that further damage by overheating or fire is prevented. |
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| 381. |
The energy stored in a watch spring is |
| A. | Kinetic energy |
| B. | Potential energy |
| C. | Heat energy |
| D. | Chemical energy |
| Answer» B. Potential energy | |
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Explanation: 0 |
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| 382. |
Cryogenic is a science deals with - |
| A. | High Temperatures |
| B. | Low Pressure |
| C. | High Pressure |
| D. | Low Temperature |
| Answer» D. Low Temperature | |
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Explanation: Cryogenics is the branch of physics that deals with the production and effects of very low temperatures. |
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| 383. |
`Short-sight' in human eye can be corrected by using proper – |
| A. | convex lens |
| B. | concave lens |
| C. | cylindrical lens |
| D. | bifocal lens |
| Answer» B. concave lens | |
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Explanation: Scintillation or twinkling is generic terms for variations in apparent brightness or position of a distant luminous object viewed through a medium. If the object lies outside the Earth's atmosphere, as in the case of stars and planets, the phenomenon is termed astronomical scintillation; within the atmosphere, the phenomenon is termed terrestrial scintillation. |
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| 384. |
What is the reason for twinkling of stars? |
| A. | Dispersion of light |
| B. | Total internal reflection |
| C. | Atmospheric reflection |
| D. | Atmospheric refraction |
| Answer» D. Atmospheric refraction | |
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Explanation: Seismometers are instrument that measures motion of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions and other seismic sources. Records of seismic waves allow seismologists to map the interior of the earth and locate and measure the size of these different sources.Seismograph is another Greek term meaning to draw siesmo waves. |
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| 385. |
Which gas is used in filling electric bulbs - |
| A. | Neon |
| B. | Argon |
| C. | Krypton |
| D. | Radon |
| Answer» B. Argon | |
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Explanation: Argon is used to fill incandescent light bulbs to inhibit the evaporation of the tungsten filaments and increase bulb life. |
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| 386. |
Ball pen functions on the principle of : |
| A. | Viscosity |
| B. | Boyle's Law |
| C. | Gravitational force |
| D. | Surface tension |
| Answer» D. Surface tension | |
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Explanation: The ballpoint pen is one of the most simple and yet ubiquitous devices whose function depends on surface tension. With a pen held upright, gravity and surface tension act in concert to get ink onto the ball. |
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| 387. |
A man cannot see clearly beyond 10 meters. The disease he suffers from : |
| A. | Far sight |
| B. | Myopia |
| C. | Cataract |
| D. | Hypermetropia |
| Answer» B. Myopia | |
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Explanation: The man suffers from myopia, a vision condition in which close objects are seen clearly, but objects farther away appear blurred. Nearsightedness occurs if the eyeball is too long or the cornea, the clear front cover of the eye, has too much curvature. As a result, the light entering the eye isn't focused correctly and distant objects look blurred. |
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| 388. |
The S.I. unit of electric charge is – |
| A. | ampere |
| B. | coulomb |
| C. | e.s.u |
| D. | Kelvin |
| Answer» B. coulomb | |
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Explanation: The SI unit of quantity of electric charge is the coulomb, which is equivalent to about 6.242x10^18 e (e is the charge of a proton). Hence, the charge of an electron is approximately -1.602x10^-19 C. The coulomb is defined as the quantity of charge that has passed through the cross section of an electrical conductor canying one ampere within one second. |
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| 389. |
Light beam which is highly directional is called: |
| A. | eraser |
| B. | grazer |
| C. | maser |
| D. | laser |
| Answer» D. laser | |
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Explanation: Laser light is very different from normal light. It is very directional, has a very tight beam and is very strong and concentrated. The light released is monochromatic. It contains one specific wavelength of light (one specific colour). |
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| 390. |
Permissible noise level at Residential area during night time is : |
| A. | 45 dB |
| B. | 55 dB |
| C. | 75 dB |
| D. | 80 dB |
| Answer» A. 45 dB | |
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Explanation: As per the norm, the permissible noise level in residential areas is 45 db during night time, 55 db during day and in commercial areas it is 55 db during night and 65 db during day. |
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| 391. |
When milk is churned, the cream separates from it clue to: |
| A. | Frictional force |
| B. | Centrifugal force |
| C. | Gravitation al force |
| D. | Viscous forces |
| Answer» B. Centrifugal force | |
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Explanation: The extraction of cream happens because of the work of centrifugal force which works outward. The separation of cream from milk is based on the fact that when liquids of different specific gravities revolve around the same centre at the same distance with the same angular velocity, a greater centrifugal force is exerted on the heavier liquid than on the lighter one. Milk can be regarded as two liquids of different specific gravities, the serum and the fat. |
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| 392. |
Moving electric charge produces - |
| A. | magnetic field |
| B. | sound waves |
| C. | light rays |
| D. | heat waves |
| Answer» A. magnetic field | |
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Explanation: An electric charge always produces an electric field, regardless of speed, and a moving charge generates a magnetic field. An electric current passing through a conductor produces a magnetic field because it has many charges in motion. |
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| 393. |
The process of union of two or more molecules of a substance to form a large single molecule is called : |
| A. | Fusion |
| B. | Diffusion |
| C. | Polymerization |
| D. | Synthesis |
| Answer» C. Polymerization | |
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Explanation: Polymerisation is the chemical process of monomers joining together to form polymers, often it takes many thousands of monomers to make a single polymer. |
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| 394. |
When a barometer reading suddenly recedes, it indicates that climate – |
| A. | will be very warm |
| B. | will be extremely stormy |
| C. | will remain cold |
| D. | incessant rain for at least 48 hours |
| Answer» B. will be extremely stormy | |
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Explanation: In summer, when the barometer falls suddenly, a thunderstorm can be expected, and if it does not rise again upon its cessation, the weather will probably continue unsettled for several days. In summer, when a thunderstorm happens, there is little or no depression of the barometer. |
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| 395. |
Which colour of light shows maximum deviation when passed through a prism? |
| A. | White |
| B. | Red |
| C. | Violet |
| D. | Green |
| Answer» C. Violet | |
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Explanation: The angle of deviation, by which the light of a particular wavelength gets deviated on passing through a medium, depends upon the refractive index of the medium, as encountered by that light wavelength. The smaller the wavelength of the passing light, the greater is the refractive index observed. |
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| 396. |
The best material for the core of a transformer is – |
| A. | stainless steel |
| B. | mild steel |
| C. | hard steel |
| D. | soft iron |
| Answer» D. soft iron | |
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Explanation: Iron has a very large magnetic response: it greatly amplifies an applied magnetic field. The transformer's ability to transfer energy depends on the strength of the magnetic field, so it is very helpful if the field is amplified. The input energy can then be lower while still having the same effect. |
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| 397. |
Electron microscope was invented by – |
| A. | Knoll and Ruska |
| B. | Robert. Koch |
| C. | Lecuwenhock |
| D. | C.P. Swanson |
| Answer» A. Knoll and Ruska | |
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Explanation: It is widely accepted that the first prototype of an electron microscope was built by Ernst Ruska and Max Knoll in 1931; it was not more powerful than an optical microscope, but it demonstrated the principle that is still used in today's sophisticated and powerful instruments, and earned its builders a share of a Nobel Prize. An electron microscope uses a beam of electrons to illuminate a specimen and produce a magnified image. |
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| 398. |
Hydrogen bomb is based on the principle of - |
| A. | Double decomposition |
| B. | Artificial radioactivity |
| C. | Nuclear fission |
| D. | Nuclear fusion |
| Answer» D. Nuclear fusion | |
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Explanation: Hydrogen Bomb is based on the principle of Nuclear Fusion. Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles. |
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| 399. |
The period of revolution of a geo- stationary satellite is – |
| A. | 365 days |
| B. | 30 days |
| C. | 24 hours |
| D. | changing continuously |
| Answer» C. 24 hours | |
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Explanation: A geosynchronous satellite is a satellite in geosynchronous orbit, with an orbital period the same as the Earth's rotation period. Such a satellite returns to the same position in the sky after each sidereal day, and over thecourse of a day traces out a path in the sky. A special case of geosynchronous satellite is the geostationary satellite, which has a geostationary orbit - a circular geosynchronous orbit directly above the Earth's equator. |
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| 400. |
The device which converts sound energy into electrical enemy is called – |
| A. | Amplifier |
| B. | Speaker |
| C. | Microphone |
| D. | Transmitter |
| Answer» C. Microphone | |
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Explanation: A microphone converts sound energy to electrical energy this energy level is used as an output using same energy level, amplified or it could be used to record those same energy output and pattern too be played again. Sound 'waves strike a plastic or thin metal diaphragm, causing in to move an attached coil within a strong magnetic field. The induced current duplicates the frequency of the sound wave. |
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