McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 251. |
What is the minimum escape velocity of rocket to be launched into space? |
| A. | 5 Km/Sec. |
| B. | 6 Km/Sec. |
| C. | 11 Km/Sec. |
| D. | 15 Km/Sec. |
| Answer» C. 11 Km/Sec. | |
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Explanation: On the surface of the Earth, the escape velocity is about 11.2 kilometers per second 06.96 mi/s), which is approximately 34 times the speed of sound (Mach 34) and several times the muzzle velocity of a rifle bullet (up tob 1.7 km/s). However, at 9,000 km altitude in "space", it is slightly less than 7.1 km/s. In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero. |
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| 252. |
How much calorie of energy is released by a boiled egg? |
| A. | 40 |
| B. | 50 |
| C. | 60 |
| D. | 77 |
| Answer» D. 77 | |
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Explanation: 77-78 calories are released in a large size boiled egg. Boiled eggs are eggs (typically chicken eggs) cooked by immersion in boiling water with their shells unbroken. |
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| 253. |
Which combination of colour is the most convenient during day and night time? |
| A. | Organe and blue |
| B. | While and black |
| C. | Yellow and blue |
| D. | Red and green |
| Answer» D. Red and green | |
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Explanation: Red and green is the most convenient combination during day and night time because of very precise visibility. In modem colour theory, also known as the RGB colour model, red, green and blue are additive primary colours. Red, green and blue light combined together makes white light, and these three colours, combined in different mixtures, can produce almost any colour. This is the principle used to make the colours on computer screen and television. |
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| 254. |
The instrument that measures and records the relative humidity of air is – |
| A. | Hydrometer |
| B. | Hygrometer |
| C. | Lactometer |
| D. | Barometer |
| Answer» B. Hygrometer | |
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Explanation: A hygrometer is an instrument used for measuring the moisture content in the environment. Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity. |
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| 255. |
In a Laser (say neon laser) all the atoms emit the light waves of – |
| A. | Same frequency |
| B. | Same amplitude |
| C. | Same phase |
| D. | All of the above |
| Answer» D. All of the above | |
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Explanation: In a Laser all the atoms emit the light waves of same frequency, amplitude and phase. A laser is a device that emits light (electromagnetic radiation) through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation. |
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| 256. |
Which of the following celestial bodies contains abundant quantities of helium-3, a potential source of energy? |
| A. | Earth |
| B. | Moon |
| C. | Venus |
| D. | Saturn |
| Answer» B. Moon | |
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Explanation: The Moon and other celestial bodies contain a vast amount of natural resources. One, and in abundance, is helium-3. It is estimated that forty tons of it can meet twenty five percent of the global energy demand for one year. |
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| 257. |
Smog is a combination of – |
| A. | Air and water vapours |
| B. | Water and smoke |
| C. | Fire and water |
| D. | Smoke and fog |
| Answer» D. Smoke and fog | |
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Explanation: Smog is a type of air pollution; the word "smog" was coined in the early 20th century as a portmanteau of the words smoke and fog to refer to smoky fog. The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid 20th century. This kind of smog is caused by the burning of large amounts of coal within a city; this smog contains soot particulates from smoke, sulfur dioxide and other components. |
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| 258. |
When white light passes through a glass prism we get a spectrum on the other side of the prism. In the emergent beam the ray which is deviated least is - |
| A. | the violet ray |
| B. | the red ray |
| C. | the green ray |
| D. | the blue ray |
| Answer» B. the red ray | |
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Explanation: Red is deviated the least and violet the most. |
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| 259. |
Study of life in outer space is known as - |
| A. | endbiology |
| B. | exobiology |
| C. | enterbiology |
| D. | neobiology |
| Answer» B. exobiology | |
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Explanation: Exobiology is a branch of biology concerned with the search for life outside the Earth and with th effects of extra-terrestrial environments on living organisms. |
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| 260. |
Lens is made up of – |
| A. | Pyrex glass |
| B. | Flint glass |
| C. | Ordinary glass |
| D. | Cobalt glass |
| Answer» B. Flint glass | |
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Explanation: Flint glass is optical glass that has relatively high refractive index and low Abbe number (high dispersion). A concave lens of flint glass is commonly combined with a convex lens of crown glass to produce an achromatic doublet lens because of their compensating optical properties, which reduces chromatic aberration (colour defects). |
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| 261. |
The time period of a pendulum when taken to the Moon would: |
| A. | remain the same |
| B. | decrease |
| C. | become zero |
| D. | increase |
| Answer» D. increase | |
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Explanation: Since the pendulum rate will increase with an increase in gravity, and local gravity varies with latitude and elevation on Earth, pendulum clocks must be readjusted to keep time after a move. For example, a pendulum clock moved from sea level to 4000 feet will lose 16 seconds per day. |
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| 262. |
Pieces of camphor placed on water move about rapidly. This is because of - |
| A. | diffusion |
| B. | viscosity |
| C. | surface tension |
| D. | capillarity |
| Answer» C. surface tension | |
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Explanation: The Camphor slowly dissolves in the water lowering the latter’s surface tension in the immediate neighborhood. The stronger pull exerted by the uncontaminated portion of water brings about a movement of the surface and the camphor particles are carried along with it. |
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| 263. |
Lightning is caused due to – |
| A. | electric power |
| B. | electric discharge |
| C. | electric leak |
| D. | electric pressure |
| Answer» B. electric discharge | |
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Explanation: Lightning is a discharge of electrical energy that builds up within a storm. The charges develop because a storm causes air to move around which rubs against itself to generate electrical charges. Eventually the charge increases to a point where the electricity can flow through the air |
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| 264. |
Sprayer functions on – |
| A. | Bernouli’s principle |
| B. | Archeinecle's principle |
| C. | Pascal's law |
| D. | Floatation principle |
| Answer» A. Bernouli’s principle | |
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Explanation: Bernoulli's principle states that as the speed of a moving fluid (liquid or gas) increases, the pressure within the liquid decreases. In the case of a sprayer, when the plunger is pushed in, the air flows at a high velocity through a nozzle, creating a region of low pressure above the metal tube. The higher pressure of the atmospheric air causes the liquid to rise up to the metal tube and come out as spray. |
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| 265. |
Waves that are required for long distance wireless communication are – |
| A. | Infrared rays |
| B. | Ultraviolet rays |
| C. | Radio waves |
| D. | Microwaves |
| Answer» C. Radio waves | |
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Explanation: Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor. With radio waves distances can be short, such as a few metres for television remote control, or as far as thousands or even millions of kilometres for deep-space radio communications. |
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| 266. |
Rise of oil a wick is due to – |
| A. | density of the oil |
| B. | viscosity of the oil |
| C. | surface tension of the oil |
| D. | pressure of the oil |
| Answer» C. surface tension of the oil | |
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Explanation: The phenomenon of rise or fall of liquid in a capillary tube is called capillarity. Oil rises through a wick due to capillarity. The narrow pores in the threads of a wick act like tiny capillaries, through which oil rises. Capillary action is the result of adhesion and surface tension. |
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| 267. |
Heat stored in water vapour is – |
| A. | specific heat |
| B. | latent heat |
| C. | absolute heat |
| D. | relative heat |
| Answer» B. latent heat | |
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Explanation: Latent heat is the heat released or absorbed by a body or a thermodynamic system during a process that occurs without a change in temperature. A typical example is a change of state of matter, meaning a phase transition such as the melting of ice or the boiling of water. So water vapor which is the end product of evaporated water has latent heat. |
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| 268. |
The layer of atmosphere used for radio- wave transmission is – |
| A. | chromosphere |
| B. | troposphere |
| C. | ionosphere |
| D. | stratosphere |
| Answer» C. ionosphere | |
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Explanation: The ionosphere is a part of the upper atmosphere and is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. |
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| 269. |
SI unit of luminous intensity is . |
| A. | lumen |
| B. | lux |
| C. | candela |
| D. | watt |
| Answer» C. candela | |
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Explanation: Luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd). |
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| 270. |
A rear-view mirror for driving is – |
| A. | plain |
| B. | concave |
| C. | convex |
| D. | inverted |
| Answer» C. convex | |
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Explanation: The kind of mirror used in the rear-view mirror must be convex mirrors, because it creates smaller, yet still upright images. Concave mirrors would create an inverted image and the cars you see are not upside down. Convex mirrors make everything smaller so this allows the driver to see a greater range of things behind him. |
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| 271. |
The important unit of a microprocessor is – |
| A. | ALU |
| B. | array of registers |
| C. | control unit |
| D. | All of the above |
| Answer» D. All of the above | |
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Explanation: The basic units or blocks of a microprocessor are ALU, an array of registers and control unit. A minimal hypothetical microprocessor might only include an arithmetic logic unit (ALU) and a control logic section. Each operation of the ALU sets one or more flags in a status register, which indicate the results of the last operation (zero value, negative number, overflow or others). |
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| 272. |
Which one of the following is an element of weather? |
| A. | Wind |
| B. | Temperature |
| C. | Humidity |
| D. | All options are correct |
| Answer» D. All options are correct | |
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Explanation: There are many elements that make up both the weather and the climate of a geographical location. The most significant of these elements are temperature, atmospheridpressure, wind, solar energy. Humidity, precipitation, and topography. |
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| 273. |
A periscope works on the principle of |
| A. | refraction |
| B. | total internal reflection |
| C. | diffraction |
| D. | reflection |
| Answer» B. total internal reflection | |
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Explanation: Total internal reflection (TIR) is the phenomenon that involves the reflection of the entire incident light off the boundary. Glass prisms can be shaped to produce total internal reflection and as such are employed in binoculars, periscopes, telescopes, and other optical instruments. For the prism used in periscope, the light rays hit the inside surface at an angle greater than the critical angle of 42 and hence they are internally reflected. |
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| 274. |
A copper disc has a hole. If the disc is heated, the size of the hole - |
| A. | increases |
| B. | decreases |
| C. | No change |
| D. | first increases and than decreases |
| 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 (sum of two radii) of the circular hole also increases. |
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| 275. |
Water cannot be used to extinguish fire caused by electric current, because – |
| A. | it may cause electrocution |
| B. | it may cause hydrolysis |
| C. | it may cause electrolysis |
| D. | it may spoil the wiring |
| Answer» A. it may cause electrocution | |
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Explanation: Using water for putting out electric fires is risky, as the firemen can be |
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| 276. |
The radiation initially produced in fluorescent tube is – |
| A. | infrared |
| B. | ultraviolet |
| C. | microwaves |
| D. | X-rays |
| Answer» B. ultraviolet | |
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Explanation: The primary radiation that is initially produced within a fluorescent lamp is analogous to that emitted by a low pressure mercury lamp. Fluorescent lamps produce UV radiation by ionizing low-pressure mercury vapour. A phosphorescent coating on the inside of the tubes absorbs the UV and converts it to visible light. |
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| 277. |
The 'four stroke petrol engine' is based on – |
| A. | Carnot-cycle |
| B. | Otto-cycle |
| C. | Diesel-cycle |
| D. | Boyle's-cycle |
| Answer» B. Otto-cycle | |
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Explanation: A four-stroke engine (also known as four-cycle) is an internal combustionn engine in which the piston completes four separate strokes—intake, compression, power, and exhaust—during two separate revolutions of the engine's crankshaft, and one single thermodynamic cycle. |
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| 278. |
The device which transfer the signal from low resistance region to high resistance region is – |
| A. | diode |
| B. | transistor |
| C. | capacitor |
| D. | inductor |
| Answer» B. transistor | |
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Explanation: A transistor transfers a signal from a low resistance to high resistance. It has two PN-junctions: one junction is forward biased and other junction is reverse biased having low resistance path and high resistance path respectively. The weak signal is introduced in the low resistance, circuit and output is taken from the high resistance circuit. |
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| 279. |
A rubber ball is dropped from a height of 2 metres. To what height will it rise if there is no loss of energy/velocity after rebounding? |
| A. | 4 metres |
| B. | 3 metres |
| C. | 2 metres |
| D. | 1 metre |
| Answer» C. 2 metres | |
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Explanation: The potential energy of a body when raised through height h is given by mgh. Each time, a normal rubber ball hits the floor, it loses one-fifth of its total energy and the rebound height is proportional to energy, so each bounce will rebound to four-fifth of the previous bounce. |
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| 280. |
The atmospheric air is held to the Earth by – |
| A. | gravity |
| B. | winds |
| C. | clouds |
| D. | rotation of the Earth |
| Answer» A. gravity | |
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Explanation: The atmosphere is an ocean of air held in place by gravity, extending from the surface to an altitude of hundreds of kilometers, the edge of space. Energy from the sun heating the air and land surface to different degrees, drives atmospheric circulation. |
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| 281. |
In which of the following processes is energy released? |
| A. | Respiration |
| B. | Photosynthesis |
| C. | Ingestion |
| D. | Absorption |
| Answer» A. Respiration | |
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Explanation: Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy in the process as they break high-energy bonds. |
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| 282. |
Atomic power plant works on the principle of – |
| A. | Fission |
| B. | Fusion |
| C. | Thermal combustion |
| D. | Combined effect of all the above three |
| Answer» A. Fission | |
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Explanation: A nuclear power plant is a facility at which energy released by the fissioning of atoms is converted to electrical energy under strictly regulated operating conditions. The major processes are the same as those in nonnuclear (conventional) power plants except that the coal or oil fired boiler is replaced by a nuclear reactor. |
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| 283. |
Which of the following circuit elements is used to 'block' DC in an electronic circuit? |
| A. | Resistances |
| B. | Capacitance |
| C. | Inductance |
| D. | Diode |
| Answer» B. Capacitance | |
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Explanation: A capacitor (originally known as condenser) is a passive two-terminal electrical component used to store energy in an electric field. Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes. |
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| 284. |
Spectacles used for viewing 3D films have – |
| A. | Bifocal lens |
| B. | Convex lens |
| C. | Concave lens |
| D. | Polaroid |
| Answer» D. Polaroid | |
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Explanation: A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye, an example of stereoscopy. To present stereoscopic images and films, two images are projected superimposed onto the same screen or display through different polarizing filters. The viewer wears low-cost eyeglasses which contain a pair of different polarizing filters. As each filter passes only that light which is similarly polarized and blocks the light polarized in the opposite direction, each eye sees a different image. |
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| 285. |
Which of the following has got more heat capacity? |
| A. | Iron piece |
| B. | Water |
| C. | Gold piece |
| D. | Benzene |
| Answer» B. Water | |
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Explanation: Heat capacity (usually denoted by a capital C, often with subscripts), or thermal capacity, is the measurable physical quantity that characterizes the amount of heat required to change a substance's temperature by a given amount. In the International System of Units (SI), heat capacity is expressed in units of joule(s) (J) per Kelvin (K). |
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| 286. |
Which of the following statements is true when we see 'rainbow'? |
| A. | We face sun and raindrops |
| B. | 11 Km/Sec. |
| C. | In light rainfall, we face Sun |
| D. | The sky remains clear and the sun is at lower position in the sky |
| Answer» C. In light rainfall, we face Sun | |
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Explanation: We see rainbows because of the geometry of raindrops. When the sun shines from behind us into the rain, incident rays of light enter the drop and are refracted inwards. They are reflected from the back surface of the raindrop, and refracted again as they exit the raindrop and return to our eyes. A rainbow is an optical and meteorological phenomenon that is caused by reflection of light in water droplets in the Earth's atmosphere, resulting in a spectrum of light appearing in the sky. |
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| 287. |
If the temperature of a place 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 vapor in an air- water mixture to the saturated vapor pressure of water at a prescribed temperature. The relative humidity of air depends not only on temperature but also on the pressure of the system of interest. If the system at State A is isobarically heated (heating with no change in system pressure) then the relative humidity of the system decreases because the saturated vapor pressure of water increases with increasing temperature. |
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| 288. |
Pulsars are : |
| A. | stars moving towards the Earth |
| B. | stars moving away from Earth |
| C. | rapidly spinning stars |
| D. | high temperature stars |
| Answer» C. rapidly spinning stars | |
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Explanation: Pulsars are celestial objects, thought to be rapidly spinning stars, that emits regular pulses of radio waves and other electromagnetic radiation at the rate of upto one thousand pulses per second. |
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| 289. |
Tungsten is used for the manufacture of the filament of an electric bulb, because – |
| A. | It is a good conductor |
| B. | It is economical |
| C. | It is malleable |
| D. | It has a very high melting point |
| Answer» D. It has a very high melting point | |
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Explanation: Tungsten is used because it has the highest melting point of all the metallic elements. It melts at 3410 degrees Celsius. When current passes through the filament it heats it up. When the filament reaches a certain temperature it starts to give off light, that's how we get a light bulb. The first successful light bulb filaments were made of carbon (from carbonized paper or bamboo). |
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| 290. |
What is the wavelength of visible spectrum? |
| A. | 1300 A° -3000 A° |
| B. | 3900 A° - 7600 A° |
| C. | 7800 A° - 8000 A° |
| D. | 8500 A° - 9800 A° |
| Answer» B. 3900 A° - 7600 A° | |
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Explanation: The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm in terms of angstrom it is in between 3900 - 7600 A°. |
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| 291. |
The shape of our Milky Way galaxy is |
| A. | circular |
| B. | elliptical |
| C. | spiral |
| D. | None of the above |
| Answer» C. spiral | |
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Explanation: The Milky Way is a barred spiral |
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| 292. |
The different colours of different stars are due to the variation of – |
| A. | temperature |
| B. | pressure |
| C. | density |
| D. | radiation from them |
| Answer» A. temperature | |
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Explanation: Shortly after blackbody radiation was understood, it was noticed that the spectra of stars look extremely similar to blackbody radiation curves of various temperatures, ranging from a few thousand Kelvin to ~50,000 Kelvin. The obvious conclusion is that stars are similar to blackbodies, and that the colour variation of stars is a direct consequence of their surface temperatures. |
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| 293. |
"Tice splitting of different colours of light in a prism is : |
| A. | Reflection of light |
| B. | Dispersion light |
| C. | Diffraction light |
| D. | Refraction of light |
| Answer» B. Dispersion light | |
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Explanation: The refractive index of many materials (such as glass) varies with the wavelength or colour of the light used, a phenomenon known as dispersion. This causes light of different colours to be refracted differently and to leave the prism at different angles, creating an effect similar to a rainbow. In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency. |
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| 294. |
A boat will submerge when it displaces water equal to its own: |
| A. | volume |
| B. | weight |
| C. | surface area |
| D. | density |
| Answer» B. weight | |
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Explanation: A boat will float when the weight of the water it displaces equals the weight of the boat and anything will float if it is shaped to displace its own weight of water before it reaches the point where it will submerge. Floating of the boat works on the principle of buoyancy force which is an upward force exerted by a liquid, gas or other fluid, that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. |
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| 295. |
Anemometer is used to measure – |
| A. | wind direction |
| B. | wind velocity |
| C. | pressure gradient |
| D. | wind speed and time |
| Answer» B. wind velocity | |
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Explanation: An anemometer is a device for measuring wind speed, and is a common weather station instrument. The first known description of an anemometer was given by Leon Battista Alberti around 1450. |
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| 296. |
The device used for locating submerged objects under sea is – |
| A. | sonar |
| B. | radar |
| C. | laser |
| D. | maser |
| Answer» A. 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. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. |
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| 297. |
The working principle of a 'Washing machine' is : |
| A. | centrifugation |
| B. | dialysis |
| C. | reverse osmosis |
| D. | diffusion |
| Answer» A. centrifugation | |
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Explanation: The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifical force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes. |
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| 298. |
Instrument used to measure the force and velocity of the wind is – |
| A. | Ammeter |
| B. | Anemometer |
| C. | Altimeter |
| D. | Audiometer |
| Answer» B. Anemometer | |
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Explanation: An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. Anemometers can be divided into two classes: those that measure the wind's speed, and those that measure the wind's pressure; but as there is a close connection between the pressure and the speed, an anemometer designed for one will give information about both. |
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| 299. |
Who measured the velocity of light first? |
| A. | Galileo |
| B. | Newton |
| C. | Romer |
| D. | Einstein |
| Answer» C. Romer | |
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Explanation: Galileo is often credited with being the first scientist to try to determine the speed of light. Galileo's experiment was carried out by the Accademia del Cimento of Florence, Italy, in 1667, with the lanterns separated by about one mile, but no delay was observed. The actual delay in this experiment would have been about 11 microseconds. The first quantitative estimate of the speed alight was made in 1676 by Romer. |
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| 300. |
Heat from the sun reaches earth by the process of – |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | All of the above |
| Answer» C. Radiation | |
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Explanation: In physics, 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. |
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