McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 101. |
Earth is also known as – |
| A. | Black planet |
| B. | Green planet |
| C. | Blue planet |
| D. | Yellow planet |
| Answer» C. Blue planet | |
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Explanation: The Earth is referred to as “the blue planet” because of the abundance of water on the planet. |
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| 102. |
The energy that can harness heat stored below the earth's surface is known as – |
| A. | thermal energy |
| B. | nuclear energy |
| C. | tidal energy |
| D. | geothermal energy |
| Answer» D. geothermal energy | |
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Explanation: Geothermal energy is thermal energy generated and stored in the Earth. The Geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%). Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW), Philippines, and Indonesia. |
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| 103. |
Green house effect is the heating up of the Earth's atmosphere which is due to – |
| A. | the ultraviolet rays |
| B. | y-rays |
| C. | the infra-red rays |
| D. | X-rays |
| Answer» C. the infra-red rays | |
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Explanation: The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through a transparent medium and are absorbed, but the longer wavelengths of the infrared reradiation from the heated objects are unable to pass through that medium. The trapping of the long wavelength radiation leads to more heating and a higher resultant temperature. |
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| 104. |
Which one of the following is used for sun glasses? |
| A. | Pyrex glass |
| B. | Flint glass |
| C. | Crooks glass |
| D. | Crystal glass |
| Answer» C. Crooks glass | |
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Explanation: A type of glass that contains cerium and other rare earths and has a high absorption of ultraviolet radiation is used in sunglasses. Sunglasses or sun glasses are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can sometimes also function as a visual aid, as variously termed spectacles or glasses exist, featuring lenses that are coloured, polarized or darkened. |
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| 105. |
If the phase difference between two points is 120° for a wave with velocity of 360 m/ and frequency 500 Hz, then path difference between the two points is – |
| A. | 1 cm |
| B. | 6 cm |
| C. | 12 cm |
| D. | 24 cm |
| Answer» D. 24 cm | |
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Explanation: 0 |
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| 106. |
The colour of sky appears blue due to – |
| A. | reflection |
| B. | refraction |
| C. | scattering of shorter wave lengths |
| D. | dispersion |
| Answer» C. scattering of shorter wave lengths | |
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Explanation: The sunlit sky is blue because air scatters short-wavelength light more than longer wavelengths. Since blue light is at the short wavelength end of the visible spectrum, it is more strongly scattered in the atmosphere than long wavelength red light. The result is that the human eye perceives blue when looking toward parts of the sky other than the sun. |
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| 107. |
Materials for rain proof coats and tents owe their water proof properties to – |
| A. | Surface tension |
| B. | Viscosity |
| C. | Specific gravity |
| D. | Elasticity |
| Answer» A. Surface tension | |
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Explanation: Materials for rain proof coats and tents owe their water proof properties to Surface Tension. The surface of a liquid behaves like an elastic membrane and therefore, has a tendency to contract. This property of liquid is called Surface Tension. |
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| 108. |
If no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. Which law states this? |
| A. | Newton first law |
| B. | Newton second law |
| C. | Newton third law |
| D. | Principle of conservation of linear momentum |
| Answer» D. Principle of conservation of linear momentum | |
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Explanation: Principle of conservation of linear momentum states if no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. |
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| 109. |
A particle is moving in a uniform circular motion with constant speed v along a circle of radius r. The acceleration-of the particle is – |
| A. | zero |
| B. | V/r |
| C. | V/r² |
| D. | V²/r |
| Answer» D. V²/r | |
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Explanation: When a particle is moving in a uniform circular motion with constant speed and radius. the acceleration of the particle is given by v2/r. The particle will exhibit centripetal acceleration. |
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| 110. |
Which of the following are bad conductors of electricity? |
| A. | Mica and Quartz |
| B. | Metals and Rubber |
| C. | Metals and Mica |
| D. | Mica and Rubber |
| Answer» A. Mica and Quartz | |
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Explanation: Metals are good conductors of electricity, because they have free electrons. Micaand quartz are examples of insulators (bad conductors of electricity), they don't have free electrons. |
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| 111. |
What was invented by 'Zacharias Janssen'? |
| A. | Telescope |
| B. | Microscope |
| C. | Stethoscope |
| D. | Periscope |
| Answer» B. Microscope | |
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Explanation: In Boreel's investigation Johannes also claimed his father, Zacharias Jansen, invented the compound microscope in 1590. |
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| 112. |
The unit of measurement of noise is – |
| A. | Decibel |
| B. | Hertz |
| C. | Amplifier |
| D. | Acoustics |
| Answer» A. Decibel | |
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Explanation: The decibel (dB) is the unit used to measure the intensity of sound or noise level. It is given in terms of a logarithmic function of a ratio of power intensities. One decibel is one tenth of one bel, named in honor of Alexander Graham Bell who was the inventor of the telephone and phonograph. |
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| 113. |
Which of the following devices can be used to detect radiant heat? |
| A. | Liquid thermometer |
| B. | Six's maximum and minimum thermometer |
| C. | Constant volume air thermometer |
| D. | Thermopile |
| Answer» D. Thermopile | |
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Explanation: Based on the thermoelectric effect, the thermopile can be used as a heat sensor to measure thermal radiation. A thermopile is made of thermocouple junction pairs connected electrically in series. Thermocouples near the ground measures radiant energy. |
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| 114. |
In which one of the following the phenomenon of total internal reflection of light is used? |
| A. | Formation of mirage |
| B. | Working of binoculars |
| C. | Formation of rainbow |
| D. | Twinkling of stars |
| Answer» C. Formation of rainbow | |
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Explanation: When the angle of incidence is greater than the critical angle, no refraction occurs. Instead, the incident beam is reflected, obeying the Law of Reflection. This is called Total internal reflection. In the formation of a rainbow, Total Internal Reflection occurs at the rear of the raindrop - the water-to-air interface. |
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| 115. |
Period of oscillation of 3 cm microwaves in seconds is |
| A. | 1 x 10¹⁰ |
| B. | 1 x 10⁻¹⁰ |
| C. | 0.01 |
| D. | 0.001 |
| Answer» B. 1 x 10⁻¹⁰ | |
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Explanation: The period of oscillation of 3 cm microwaves is 1 x 10^-10 (Physics, Volume 1, by Halliday). The period of oscillation is the smallest interval of time in which a system undergoing oscillation returns to the state it was in at the beginning of the oscillation. |
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| 116. |
When two ice cubes are pressed together, they join to form one cube. Which one of the following helps to hold them together? |
| A. | Hydrogen bond formation |
| B. | Vander waals forces |
| C. | Covalent attraction |
| D. | Dipole interaction |
| Answer» A. Hydrogen bond formation | |
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Explanation: When two ice cubes are pressed together, they join to form one cube due to hydrogen bond. |
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| 117. |
For which Diode is used? |
| A. | modulation |
| B. | oscillation |
| C. | amplification |
| D. | purificationin |
| Answer» D. purificationin | |
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Explanation: The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). This unidirectional behavior is called rectification or verification and is used to convert alternating current to direct current, including extraction of modulation from radio signals in radio receivers—these diodes are forms of rectifiers diode is a two-terminal electronic component with an asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other. |
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| 118. |
The force which opposes the relative motion between different layers of liquid or gases is called – |
| A. | Critical Velocity |
| B. | Streamline Flow |
| C. | Terminal Velocity |
| D. | Viscous Force |
| Answer» D. Viscous Force | |
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Explanation: Critical Velocity – The maximum velocity upto which fluid motion is streamline is called Critical Velocity. Streamline Flow – If velocity of all fluid particles is same all the time then it can be said in streamline flow. |
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| 119. |
Water has maximum density at ___. |
| A. | 0 C |
| B. | -15 C |
| C. | 4 C |
| D. | 15 C |
| Answer» C. 4 C | |
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Explanation: Water has maximum density at 4 degrees C turns out to be the temperature at which liquid water has the highest density. If you heat it or cool it, it will expand. |
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| 120. |
Who among the following developed the technology of under-ground nuclear explosion? |
| A. | Dr. Homi J. Bhabha |
| B. | Dr. Vikram Sarabhai |
| C. | Dr. Raja Ramanna |
| D. | Dr. P. K. Iyengar |
| Answer» A. Dr. Homi J. Bhabha | |
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Explanation: Homi Jehangir Bhabha was an Indian nuclear physicist, founding director, and professor of physics at the Tata Institute of Fundamental Research. Colloquially known as "father of Indian nuclear programme," Bhabha gained international prominence after deriving a correct expression for the probability of scattering positrons by electrons, a process now known as Bhabha scattering. |
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| 121. |
Sensitivity of the human eye is maximum in the – |
| A. | Violet region |
| B. | Green region |
| C. | Blue region |
| D. | Red region |
| Answer» B. Green region | |
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Explanation: The human eye is sensible to light wave which wavelength is roughly between 400 nm and 700 nm. When illumination is enough (in daylight) the maximum sensitivity is in the green region at 555 nm. |
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| 122. |
The speed of light in air is – |
| A. | 3 x 10⁸ m/s |
| B. | 3 x 10⁻⁸ cm/s |
| C. | 8 x 10³ m/s |
| D. | Infinity |
| Answer» A. 3 x 10⁸ m/s | |
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Explanation: Speed of light (in Media) = Speed of Light (in Vacuum) / Refreactive Index of Material. Speed of light in air as taken generally is 3 X 10 power 8 meter per second. |
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| 123. |
The speed of light with the rise in the temperature of the medium : |
| A. | Increases |
| B. | Decreases |
| C. | Remains unaltered |
| D. | Drops suddenly |
| Answer» C. Remains unaltered | |
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Explanation: The speed of light with the rise in the temperature of the medium remains unaltered because speed of light doesn't depend on temperature. It does depend, however, on the refractive index of the substance it is travelling through. The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. |
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| 124. |
A rocket works on the principle of conservation of ______. |
| A. | mass |
| B. | linear momentum |
| C. | energy |
| D. | angular momentum |
| Answer» B. linear momentum | |
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Explanation: A rocket works by expelling gases from one end at a very high velocity. The escaping gases have a very high speed and this with their mass translates to a very large momentum. |
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| 125. |
The swing of a spinning cricket ball in air can be explained on the basis of – |
| A. | Sudden change in wind direction. |
| B. | Buoyancy of air. |
| C. | Turbulence caused by wind. |
| D. | Bernoulli's theorem. |
| Answer» C. Turbulence caused by wind. | |
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Explanation: The main theory of swing bowling surrounded turbulent and laminar airflow. Laminar air separates from the surface of the ball earlier than turbulent flow air, so that the separation point moves toward the front of the ball on the laminar side. On the turbulent flow side it remains towards the back; inducing a greater lift force on the turbulent airflow side of the ball. |
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| 126. |
Which layer of the earth’s atmosphere reflects back the radio waves to the earth’s surface? |
| A. | Ionosphere |
| B. | Stratosphere |
| C. | Mesosphere |
| D. | Exosphere |
| Answer» A. Ionosphere | |
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Explanation: Long distance propagation of radio waves depends on an invisible layer of charged particles, which envelops the Earth. This layer of charged particles known as the ionosphere has been in existence for millions of years. For those, who pioneered the long distance radio communication during the early part of the twentieth century, the ionosphere came as a boon. |
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| 127. |
What is the process of melting also called? |
| A. | Fusion |
| B. | Galvanisation |
| C. | Crystallisatiorn |
| D. | Evaporation |
| Answer» A. Fusion | |
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Explanation: Melting, or fusion. is a physical process that results in the phase transition of a substance from a solid to a liquid. |
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| 128. |
A man inside an artificial satellite feels weightlessness because the force of attraction due to earth is – |
| A. | zero at that place |
| B. | is balanced by the force of attraction due to moon |
| C. | equal to the centripetal force |
| D. | non-effective due to particular design of the satellite |
| Answer» A. zero at that place | |
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Explanation: Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero. |
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| 129. |
'Shock-absorbers are usually made of steel as it – |
| A. | is not brittle |
| B. | has lower elasticity |
| C. | has higher elasticity |
| D. | has no ductile property |
| Answer» C. has higher elasticity | |
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Explanation: A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Steel is an alloy made by combining iron and other elements, the most common of these being carbon. |
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| 130. |
What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it? |
| A. | Elasticity |
| B. | Strain |
| C. | Elastic Limit |
| D. | Stress |
| Answer» C. Elastic Limit | |
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Explanation: The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape. |
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| 131. |
With the increase of pressure, the boiling point of any substance – |
| A. | Increases |
| B. | Decreases |
| C. | Remains Same |
| D. | Becomes zero |
| Answer» A. Increases | |
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Explanation: The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form. |
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| 132. |
Among the following materials sound travels fastest in – |
| A. | Steel |
| B. | Air |
| C. | Vacuum |
| D. | Water |
| Answer» A. Steel | |
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Explanation: The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air. |
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| 133. |
Velocity of the sound is minimum in - |
| A. | Steel |
| B. | Vacuum |
| C. | Water |
| D. | Air |
| Answer» B. Vacuum | |
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Explanation: The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air. |
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| 134. |
Safety fuse wire used in domestic electrical appliances is made of metal of low |
| A. | Resistance |
| B. | Melting point |
| C. | Specific gravity |
| D. | Conductance |
| Answer» B. Melting point | |
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Explanation: The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point. |
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| 135. |
The following particles move with same kinetic energy. Which of them has maximum momentum? |
| A. | Electron |
| B. | Proton |
| C. | Deutron |
| D. | Alpha Particle |
| Answer» D. Alpha Particle | |
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Explanation: The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P^2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass. |
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| 136. |
A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect? |
| A. | Near the bottom |
| B. | In the middle of the bottom |
| C. | Near the neck |
| D. | Bubbles remain distributed uniformly |
| Answer» C. Near the neck | |
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Explanation: When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top. |
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| 137. |
Lambert's law is related to – |
| A. | Reflection |
| B. | Refraction |
| C. | Interference |
| D. | Illumination |
| Answer» D. Illumination | |
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Explanation: In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law. |
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| 138. |
When a detergent is added to pure water, its surface tension – |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | becomes infinite |
| Answer» B. decreases | |
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Explanation: When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension. |
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| 139. |
Small bubbles are perfectly spherical because of – |
| A. | Gravity |
| B. | Pressure |
| C. | Viscosity |
| 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 an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law. |
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| 140. |
The final image in a simple microscope is – |
| A. | real, diminished and inverted |
| B. | real, magnified and erect |
| C. | virtual, magnified and erect |
| D. | virtual, diminished and erect |
| Answer» C. virtual, magnified and erect | |
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Explanation: A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object. |
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| 141. |
A radioactive substance emits? |
| A. | alpha particle |
| B. | beta particle |
| C. | gamma particle |
| D. | all of the three |
| Answer» D. all of the three | |
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Explanation: Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow. |
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| 142. |
A single fixed pulley is used to draw water from a well because – |
| A. | efficiency is 100% |
| B. | velocity ratio is low |
| C. | mechanical advantage is high |
| D. | force is applied in a convenient direction |
| Answer» D. force is applied in a convenient direction | |
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Explanation: A single fixed pulley is used to lift a load upwards by applying efforts downward's. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well. |
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| 143. |
Hyperrnetropia or longsight can be corrected by using : |
| A. | Bifocal lenses |
| B. | Cylindrical lenses |
| C. | Concave lenses |
| D. | Convex lenses |
| Answer» D. Convex lenses | |
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Explanation: It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range. |
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| 144. |
Stars appear twinkling because of ______ of light. |
| A. | Reflection |
| B. | Scattering |
| C. | Emission |
| D. | Absorption |
| Answer» B. Scattering | |
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Explanation: The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling. |
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| 145. |
In mirrors the back surface is coated with a thin layer of |
| A. | Mercury |
| B. | Silver |
| C. | Red oxide |
| D. | Silver nitrate |
| Answer» B. Silver | |
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Explanation: In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface. |
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| 146. |
A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments – |
| A. | is zero |
| B. | depends on the total mass of all the fragments |
| C. | depends on the speeds of various fragments |
| D. | is infinity |
| Answer» A. is zero | |
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Explanation: In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum. |
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| 147. |
Sound energy passing per second through a unit area held perpendicular is called - |
| A. | Intensity |
| B. | Frequency |
| C. | Amplitude |
| D. | Quality |
| Answer» A. Intensity | |
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Explanation: Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound. |
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| 148. |
Which one of the following is used to remove Astigmatism for a human eye? |
| A. | Concave lens |
| B. | Convex lens |
| C. | Cylindrical lens |
| D. | Prismatic lens |
| Answer» C. Cylindrical lens | |
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Explanation: A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would. |
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| 149. |
Speed of sound in air is unaffected by change in : |
| A. | Pressure |
| B. | Humidity |
| C. | Temperature |
| D. | Volume |
| Answer» A. Pressure | |
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Explanation: The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant. |
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| 150. |
The audio signals of TV are : |
| A. | Amplitude modulated |
| B. | Frequency modulated |
| C. | Unmodulated |
| D. | Velocity modulated |
| Answer» B. Frequency modulated | |
| Explanation: In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video. | |
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