McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 201. |
The metal used to make lightning conductors is – |
| A. | Iron |
| B. | Aluminum |
| C. | Copper |
| D. | Zinc |
| Answer» C. Copper | |
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Explanation: A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution. |
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| 202. |
The phenomenon of radioactivity was discovered by - |
| A. | Marie Curie |
| B. | Pierre Curie |
| C. | Henri Becquerel |
| D. | J.J. Thomson |
| Answer» C. Henri Becquerel | |
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Explanation: In 1896 Henri Becquerel was using naturally fluorescent minerals to study the properties of x-rays |
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| 203. |
If the velocity-time graph of a particle is represented by y = mt + c, then the particle is moving with– |
| A. | constant speed |
| B. | constant velocity |
| C. | constant acceleration |
| D. | varying acceleration |
| Answer» C. constant acceleration | |
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Explanation: In this case the given equation shows that that the velocity is linear with time and therefore the particle is moving with constant acceleration because for a particle to acquire constant acceleration the graph of the velocity time graph should be in linear with the time function. |
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| 204. |
In a photocell light energy is converted into – |
| A. | Potential energy |
| B. | Chemical energy |
| C. | Heat energy |
| D. | Electrical energy |
| Answer» D. Electrical energy | |
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Explanation: Photocells are scientifically known as photo-resistors. A photo-resistor or light dependent resistor (LDR) is a resistor whose resistance decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photo-resistor is made of a high resistance semiconductor. If light falling on the device is of high enough frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. |
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| 205. |
A storm is predicted if atmospheric pressure – |
| A. | Rises suddenly |
| B. | Rises gradually |
| C. | Falls suddenly |
| D. | Falls gradually |
| Answer» C. Falls suddenly | |
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Explanation: Atmospheric pressure is basically the weight of air in the atmosphere above the reservoir, so the level of mercury continues to change until the weight of mercury in the glass tube is exactly equal to the weight of air above the reservoir. In areas of low pressure, air is rising away from the surface of the earth more quidkly than it can be replaced by air flowing in from surrounding areas. This reduces the weight of air above the reservoir so the mercury level drops to a lower level. |
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| 206. |
The smallest unit of classification is - |
| A. | Species |
| B. | Genus |
| C. | Family |
| D. | Order |
| Answer» A. Species | |
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Explanation: Species is the smallest and basic unit of classification. Kingdom is the largest unit of Classification. |
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| 207. |
A concave lens always forms an image which is – |
| A. | Real and erect |
| B. | Virtual and erect |
| C. | Real and inverted |
| D. | Virtual and inverted |
| Answer» B. Virtual and erect | |
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Explanation: Concave lens possesses at least one surface that curves inwards. It is a diverging lens, spreading out those light rays that have been refracted through it. A concave lens is thinner at its centre than at its edges, and is used to correct short-sightedness (myopia). After light rays have passed through the lens, they appear to come from a point called the principal focus. The image formed by a concave lens is virtual, upright, and smaller than the object, and it cannot be projected onto a screen. |
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| 208. |
One can distinguish a telescope from a microscope by observing – |
| A. | length |
| B. | colour |
| C. | size of the lens |
| D. | length and size of the lens |
| Answer» D. length and size of the lens | |
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Explanation: Telescope and Microscope are two scientific instruments that serve their purposes differently. One of the main differences between a telescope and a microscope is that a telescope is used to view things that are far whereas a microscope is used to view things that are very near. Another important difference between telescope and microscope is that the focal length or the distance from the focal point to the lens is different in these two scientific instruments. |
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| 209. |
The sound produced by a bat is – |
| A. | audible |
| B. | subsonic |
| C. | infrasonic |
| D. | ultrasonic |
| Answer» D. ultrasonic | |
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Explanation: Although bats use echolocation to detect their prey, and find their way around in the dark, the sounds which they emit are 'ultrasonic', which is another way of saying they are beyond the range of normal human hearing. Ultrasound is a cyclic sound pressure wave with a frequency greater than the upper limit of thehuman hearing range. Ultrasound is thus not separated from "normal" (audible) sound based on differences in physical properties, only the fact that humans cannot hear it. |
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| 210. |
The image of an object formed on the retina of the eye is - |
| A. | virtual and upright |
| B. | virtual and inverted |
| C. | real and inverted |
| D. | Real and upright |
| Answer» C. real and inverted | |
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Explanation: Although the image is inverted the mental interpretation of the effect on the retina is as though it is erect. |
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| 211. |
In a nuclear reactor, one of the following is used as a fuel. |
| A. | Coal |
| B. | Uranium |
| C. | Radium |
| D. | Diesel |
| Answer» B. Uranium | |
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Explanation: Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 has the distinction of being the only naturally occurring fissile isotope. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor. Another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. |
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| 212. |
Suns heat reaches us by – |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Reflection |
| Answer» C. Radiation | |
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Explanation: Radiation is a process in which energetic particles or energetic waves travel through vacuum, or through matter-containing media that are not required for their propagation.The sun's rays reach us in the form of electromagnetic radiation. This type of radiation covers a wide spectrum (that is a wide range of frequencies), but those from the sun are mainly infra-red, visible, and ultra-violet. |
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| 213. |
A colour-blind person cannot – |
| A. | See distant objects |
| B. | See black colour |
| C. | Distinguish between certain colours |
| D. | Have persistence of vision |
| Answer» C. Distinguish between certain colours | |
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Explanation: Colour blindness or colour vision deficiency is the inability or decreased ability to see coluor, or perceive colour differences, under normal lighting conditions. The most usual cause is a fault in the development of one or more sets of retinal cones that perceive colour in light and transmit that information to the optic nerve. This type of colour blindness is usually a sex-linked condition. |
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| 214. |
Forged documents are detected by – |
| A. | ultraviolet rays |
| B. | infra-red rays |
| C. | beta rays |
| D. | gamma rays |
| Answer» A. ultraviolet rays | |
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Explanation: Old postcards, books, signs, photos and other paper products made before the late 1930s rarely glow under a black light. Chemical bleaches and dyes used in modern papers will fluoresce under ultraviolet light. Knowing this helps to detect forged documents and distinguish reproductions in all types of ephemera. |
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| 215. |
In which medium, velocity of sound is maximum? |
| A. | Metals |
| B. | Air |
| C. | Water |
| D. | Polymer |
| Answer» A. Metals | |
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Explanation: The speed of sound is highest in solid. The speed of sound depends on the density of the medium through which it is travelling. |
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| 216. |
If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same - |
| A. | velocity |
| B. | momentum |
| C. | acceleration |
| D. | kinetic energy |
| Answer» B. momentum | |
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Explanation: If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same momentum. |
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| 217. |
The compound of a metal found in nature is called - |
| A. | Mineral |
| B. | Ore |
| C. | Flux |
| D. | Slag |
| Answer» A. Mineral | |
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Explanation: Metals are an integral part of our planet and are found in almost all rocks and soils. Most metals form compounds called minerals, which are naturally occurring, inorganic solids with regular chemical compositions and crystal structures. |
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| 218. |
Decibel is used to measure the intensity of - |
| A. | Magnetic field |
| B. | Sound |
| C. | Light |
| D. | Heat |
| Answer» B. Sound | |
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Explanation: The decibel (dB) is used to measure sound level, but it is also widely used in electronics, signals and communication. |
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| 219. |
Rainbow is seen after rain because of hanging molecules of water which act as – |
| A. | lenses |
| B. | mirrors |
| C. | prisms |
| D. | slabs |
| Answer» B. mirrors | |
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Explanation: In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. In a rainbow, raindrops in the air act as tiny prisms. Light enters the raindrop, reflects off of the side of the drop and exits. In the process, it is broken into a spectrum just like it is in a triangular glass prism. |
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| 220. |
Which of the following is a result of Surface tension? |
| A. | Gravitational pull |
| B. | Viscosity |
| C. | Capillary action |
| D. | Radiation |
| Answer» C. Capillary action | |
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Explanation: Capillary action is the result of adhesion and surface tension. Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus which turns upward. The surface tension acts to hold the surface intact, so instead of just the edges moving upward, the whole liquid surface is dragged upward. |
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| 221. |
Water is used in car radiator because of its – |
| A. | low density |
| B. | easy availability |
| C. | high specific heat capacity |
| D. | low boiling point |
| Answer» C. high specific heat capacity | |
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Explanation: Water is used in car radiators because the Specific heat capacity of water is high as a result of which it takes away the heat from engine better compared to other liquids.This is a form of coolant used in the radiator. If the radiator was to overheat the car would come to a stop. |
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| 222. |
If a metal can be drawn into wires relatively easily it is called: |
| A. | malleable |
| B. | ductile |
| C. | extractive |
| D. | tactile |
| Answer» B. ductile | |
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Explanation: Ductility is a physical property of a material associated with the ability to be hammered thin or stretched into wire without breaking. |
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| 223. |
At what temperature a body will not radiate any heat energy? |
| A. | 0° C |
| B. | 273° C |
| C. | 100° C |
| D. | -273° C |
| Answer» D. -273° C | |
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Explanation: 0 |
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| 224. |
The mirror used for the head light of a car is – |
| A. | spherical concave |
| B. | plane |
| C. | cylindrical |
| D. | parabolic concave |
| Answer» D. parabolic concave | |
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Explanation: A parabolic (or paraboloid or paraboloidal) reflector(or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. |
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| 225. |
Knot is a measure of – |
| A. | Unit of speed |
| B. | the curvature of spherical objects |
| C. | solar radiation |
| D. | intensiry of earthquake shock |
| Answer» A. Unit of speed | |
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Explanation: The Knot is a unit of speed equal to one nautical mile per hour. The ISO standerd symbol for the knot is Kn. |
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| 226. |
Stereo was invented by . |
| A. | John Barber |
| B. | Tim Berners-Lee |
| C. | Alan Blumlein |
| D. | David Brewster |
| Answer» C. Alan Blumlein | |
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Explanation: Modern stereophonic technology was invented in the 1930s by British engineer Alan Blumlein at Electric and Musical Industries in London. |
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| 227. |
How much mechanical work must be done to completely melt 1 gram of ice at 0°C? |
| A. | 4.2 J |
| B. | 80 J |
| C. | 336 J |
| D. | 2268 J |
| Answer» B. 80 J | |
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Explanation: When water at 0 degree Celsius freezes, each gram of water gives off 80 calories. The temperature of the water stays at 0 degree C until every drop has frozen. When ice at 0 degree Celsius melts, it absorbs an equal amount of heat-80 calories for each gram of ice—and its temperature remains unchanged until it has completely melted. |
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| 228. |
A bullet is fired from a rifle which recoils after firing. The ratio of kinetic energy of the rifle to that of the bullet is – |
| A. | zero |
| B. | one |
| C. | less than one |
| D. | more than one |
| Answer» A. zero | |
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Explanation: The rifle and bullet have zero momentum and zero kinetic energy to start with. When the trigger is pulled, the bullet gains some momentum in the forward direction, but this is |
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| 229. |
Which of the following is the best conductor of electricity? |
| A. | Zinc |
| B. | Copper |
| C. | Gold |
| D. | Silver |
| Answer» D. Silver | |
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Explanation: Copper and Silver Are Most Common. Silver is the best conductor of electricity because it contains a higher number of movable atoms (free electrons). |
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| 230. |
At what temperature are the temperature on Celsius and Fahrenheit scales equal? |
| A. | 273° Celsius |
| B. | -273° Celsius |
| C. | -40° Celsius |
| D. | 40° Celsius |
| Answer» C. -40° Celsius | |
| 231. |
The electric charge is stored in a device called: |
| A. | Inductor |
| B. | Capacitor |
| C. | Resister |
| D. | Transformer |
| Answer» B. Capacitor | |
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Explanation: A capacitor is a passive two- terminal electronic component that stores electrical energy in an electric field. The effect of a capacitor is known as capacitance. |
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| 232. |
SI unit for the surface tension is . |
| A. | kg/m2 |
| B. | kg/m3 |
| C. | N/m |
| D. | kg/m |
| Answer» C. N/m | |
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Explanation: Surface tension is measured in force per unit length. Its SI unit is Newton per meter. |
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| 233. |
The density of the liquid when heated |
| A. | decreases |
| B. | increases |
| C. | does not change |
| D. | may increase of decrease depending on pressure |
| Answer» A. decreases | |
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Explanation: The mass density of a material varies with temperature and pressure. Increasing the temperature of a substance (with some exceptions) decreases its density by increasing the volume of that substance. In most materials, heating the bottom of a fluid results in convection of the heat from bottom to top of the fluid due to the decrease of the density of the heated fluid. |
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| 234. |
The distance between node and adjacent antinodes is 30 cm. The wavelength is - |
| A. | 30 cm. |
| B. | 90 cm. |
| C. | 120 cm. |
| D. | 60 cm. |
| Answer» D. 60 cm. | |
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Explanation: A node is a point along a standing wave where the wave has minimal amplitude. The opposite of a node is an anti-node, a pointwhere the amplitude of the standing wave is a maximum. |
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| 235. |
When a bar magnet is cut into two equal halves, the pole strength of each piece |
| A. | becomes double |
| B. | becomes half |
| C. | becomes zero |
| D. | remains the same |
| Answer» D. remains the same | |
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Explanation: The poles remains same whether the magnet is cut into two equal half or more and also pole strength remains same but magnetic moment reduces due to decrease in the length of the magnet. If a bar magnet is suspended by a thread, it will come to rest in a position close to the north-south direction. The end of the magnetic toward the north is called north pole (N-poled of the magnet and the other end the south pole (S-pole). |
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| 236. |
A new technology which provides the ability to create an artificial world and have people interact with it is called – |
| A. | Televirtuality |
| B. | Virtual reality |
| C. | Alternate reality |
| D. | 3-D reality |
| Answer» B. Virtual reality | |
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Explanation: Virtual reality (VR) is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds. Most current virtual reality environments are primarily visual experiences, displayed either on a computer screen or through special stereoscopic displays, but some simulations include additional sensory information, such as sound through speakers or headphones. |
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| 237. |
A proton is identical to . |
| A. | the nucleus of helium |
| B. | the nucleus of a hydrogen atom |
| C. | an alpha-particle |
| D. | a beta particle |
| Answer» D. a beta particle | |
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Explanation: 0 |
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| 238. |
What should a person on a freely rotating turn table do to decrease his (angular) speed? |
| A. | Bring his hands together |
| B. | Raise his hands up |
| C. | Spread his hands outwards |
| D. | Sit down with raised hands |
| Answer» C. Spread his hands outwards | |
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Explanation: The answer is related to the conservation of angular momentum. The person on the rotating table will maintain approximately the same angular momentum during the spin. If he moves his arms in, it will reduce the rotational inertia by reducing the distance of the mass of her arms and hands from the axis of rotation. |
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| 239. |
In a rechargeable cell what kind of energy is stored within the cell? |
| A. | Electrical energy |
| B. | Potential energy |
| C. | Chemical energy |
| D. | Kinetic energy |
| Answer» C. Chemical energy | |
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Explanation: In electricity, a battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. A battery is a device that converts chemical energy directly to electrical energy. It consists of a number of voltaic cells; each voltaic cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations. |
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| 240. |
Which one of the following lenses should be used to correct the defect of astigmatism? |
| A. | Cylindrical lens |
| B. | Concave lens |
| C. | Convex lens |
| D. | Bifocal lens |
| Answer» A. Cylindrical lens | |
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Explanation: Astigmatism is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. This may be due to an irregular or toric curvature of the cornea or lens. The two types of astigmatism are regular and irregular. Irregular astigmatism is often caused by a corneal scar or scattering in the crystalline lens, and cannot be corrected by standard spectacle lenses, but can be corrected by contact lenses. |
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| 241. |
Danger signals are generally red as red light – |
| A. | is least bright |
| B. | undergoes least deviation |
| C. | has lowest velocity |
| D. | gives comfort to eye |
| Answer» B. undergoes least deviation | |
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Explanation: The primary reason why the colour red is used for danger signals is that red light is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Therefore blue which has the least wavelength of all the visible radiations is scattered the most and red which has the highest wavelength of all the colours we can see is scattered the least. |
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| 242. |
A simple microscope consists of : |
| A. | a short focus convex lens |
| B. | a long focus convex lens |
| C. | a short focus concave lens |
| D. | a long focus concave lens |
| Answer» A. a short focus convex lens | |
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Explanation: Simple microscope - light microscope consisting of a short focus single convex lens is used to produce an enlarged image. The magnifying glass was invented by Roger Bacon in 1250. In the original 'simple' microscopes, a single light path went through the object viewed and one lens, increasing the visibility of the object by some amount (magnification). |
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| 243. |
A passenger standing in a bus is thrown outward when the bus takes a sudden turn. This happens due to – |
| A. | Outward pull on him |
| B. | Inertia of motion |
| C. | Change in momentum |
| D. | Change in acceleration |
| Answer» B. Inertia of motion | |
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Explanation: This is inertia of direction. It is the ability of body to be in a state of direction of motion for example sun holds planets in a fixed elliptical path .this is one of the examples of inertia of direction. Inertia of direction is non- existent however inertia only apply to a body at rest or moving with a constant velocity. It is the property possessed by a body to resist change. |
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| 244. |
When pressure is increased the melting point of ice – |
| A. | increases |
| B. | does not change |
| C. | decreases |
| D. | depends on the impurities in the ice |
| Answer» C. decreases | |
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Explanation: In this case. if we increase the pressure on the ice the ice-water system wants to try to lower it again. It can do that by making itself fit into a smaller volume. But since water fills a smaller volume when it's liquid, rather than solid, it will go to a lower melting point — allowing more solid to become liquid and hence when we increase pressure, the melting point of ice decreases because of the inversal relationship between the pressure and melting point of ice. |
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| 245. |
What apparatus is used to locate a submerged object? |
| A. | Radar |
| B. | Sonar |
| C. | Quasar |
| D. | Pulsar |
| Answer» B. Sonar | |
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Explanation: Sonar (originally an acronym for Sound Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name "sonar": passive sonar is essentially listening for the sound made by vessels; active sonar is emitting pulses of sounds and listening for echoes. |
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| 246. |
The instrument which uses sound waves to measure the depth of oceans is – |
| A. | Radar |
| B. | Sonar |
| C. | Altimeter |
| D. | Venturimeter |
| Answer» B. Sonar | |
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Explanation: The instrument which uses sound waves to measure the depth of oceans is sonar. Sound waves can travel much faster from one point to another. Sound waves are far more accurate for measuring these vast distances. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Sonar may also be used in air for robot navigation, and SODAR is used for atmospheric investigations. |
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| 247. |
One Kilowatt hour is equal to— |
| A. | 3.6 Mega Joule |
| B. | 3.8 Mega Joule |
| C. | 3.2 Mega Joule |
| D. | 4.0 Mega Joule |
| Answer» A. 3.6 Mega Joule | |
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Explanation: The energy 1 kilowatt-hour (kWh) is 3600000 joules or 3.6 mega joule. In physics, energy is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems. However, this must be understood as an overly simplified definition, as the laws of thermodynamics demonstrate that not all energy can perform work. |
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| 248. |
Longitudinal waves cannot travel through – |
| A. | Vacuum |
| B. | Solid |
| C. | Liquid |
| D. | Gas |
| Answer» A. Vacuum | |
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Explanation: Longitudinal waves cannot travel through vacuum because such wave requires a medium such as solid liquid or air to travel through. They cannot travel through vacuum or in space. Longitudinal waves, also known as "l- waves", are waves that have the same direction of vibration as their direction of travel, which means that the movement of the medium is in the same direction as, or the opposite direction to, the motion of the wave. |
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| 249. |
Electrostatic precipitator is used to control the pollution of – |
| A. | air |
| B. | water |
| C. | noise |
| D. | thermal |
| Answer» A. air | |
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Explanation: An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic. charge. An electrostatic precipitator (ESP) or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. |
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| 250. |
The device which converts AC to DC is |
| A. | Oscillator |
| B. | Amplifier |
| C. | Rectifier |
| D. | None of these |
| Answer» C. Rectifier | |
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Explanation: A rectifier is an electrical device that converts alternating current (AC). which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury-arc valves9 solidstate diodes, silicon-controlled rectifiers and other silicon -based semiconductor switches, Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. |
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