1210+ Physics Solved MCQs

501.

A boy is standing in front of a plane mirror at a distance of 3 m from it. What is the distance between the boy and his image?

A. 3 m
B. 6 m
C. 4.5 m
D. None of these
Answer» B. 6 m
Explanation: The image formed by a plane mirror is always virtual upright, and of the same shape and size as the object it is reflecting. A virtual image is a copy of an object formed at the location from which the light rays appear to come
502.

Loudness of sound varies directly with vibrating body’s –

A. Intensity
B. Amplitude
C. Pitch
D. Quality
Answer» B. Amplitude
Explanation: Loudness of Sound: Loudness of sound depends on amplitude of vibration. Loudness of sound is directly proportional to square of amplitude of vibration.
503.

A thin oil film on a water surface appears coloured because of –

A. reflection
B. interference
C. diffraction
D. polarization
Answer» B. interference
Explanation: A thin oil film on a water surface appears coloured because of thin-film interference which involves the interference of light waves reflecting off the top surface of a film with the waves reflecting from the bottom surface.
504.

Iron which resembles Cobalt and Nickel in properties has been placed far away from these elements. This was one of the limitations of :

A. Modern periodic table
B. Newland's law of octaves
C. Dobereiner's triads
D. Mendeleev's periodic table
Answer» B. Newland's law of octaves
Explanation: Among the major limitations of Newlands Law of Octaves, some similar elements have been separated from one another while some dissimilar elements have been placed in the same column.
505.

How much is the difference of time between any two Consecutive longitudes?

A. 10min
B. 14min
C. 4 min
D. 5:30 min
Answer» C. 4 min
Explanation: The time difference between each longitude (each degree) is 4 minutes. So if it is 12 noon at Greenwich (0 degree), it would be 12:04 pm at 1 degree meridian and so on.
506.

Which of the following modes of expressing concentration is independent of temperature -

A. Molarity
B. Molality
C. Normality
D. Formality
Answer» B. Molality
Explanation: 0
507.

At boiling point of liquids, its –

A. Temperature increases
B. Atmospheric pressure increases
C. Temperature remains constant
D. Vapour pressure decreases
Answer» C. Temperature remains constant
Explanation: An interesting property of matter is that its temperature remains constant during a phase change, assuming its surrounding pressure is constant. A liquid changes into gaseous state at a constant temperature called its boiling point.
508.

Newton's first law is also known as     .

A. Law of Friction
B. Law of Momentum
C. Law of Inertia
D. Law of Motion
Answer» C. Law of Inertia
Explanation: Newton's first law of motion is also known as the law of inenrtia. It states that an object at rest stays at rest and an object inmotion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
509.

The humidity of air measured in percentage is called –

A. absolute humidity
B. specific humidity
C. relative humidity
D. all of these
Answer» C. relative humidity
Explanation: The relative humidity is the percent of saturation humidity, generally calculated in relation to saturated vapour density.
510.

Who developed the theory of Evolution?

A. Charles Darwin
B. Isaac Newton
C. Pranav Mistry
D. Galileo Galilei
Answer» A. Charles Darwin
Explanation: Summary of Darwin's Theory of Evolution: A species is a population of organisms that interbreeds and has fertile offspring.
511.

Which of the following is an insulator?

A. Mercury
B. Carbon
C. Germanium
D. Glass
Answer» D. Glass
Explanation: Insulators are materials that do not allow the transfer or that slow the transfer of heat or electricity. Some of the examples of insulators are: glass, plastic, rubber, porcelain, wood, ceramic, dry air, etc.
512.

Name the process by which bubbles from liquid are formed?

A. Effervescence
B. Surface Tension
C. Surface Energy
D. Degasification
Answer» A. Effervescence
Explanation: Effervescence is the escape of gas from an aqueous solution and the foaming or fizzing that results from a release of the gas. It leads to the formation of gas bubbles in a liquid. For example, when opening a bottle of champagne, beer or carbonated beverages such as soft drinks, the visible bubbles are produced by the escape from solution of the dissolved gas.
513.

'Parsec' is the unit measurement of –

A. Density of stars
B. Astronomical distance
C. Brightness of heavenly bodies
D. Orbital velocity of giant stars
Answer» B. Astronomical distance
Explanation: Parsec is a unit of distance used in astronomy to measure large distances to objects outside our Solar System. It is equal to about 3.26 light years (3.086 x 1013 kilometres).
514.

The phenomenon of change in direction of light when it passes from one medium to another is called -

A. Propagation
B. Reflection
C. Refraction
D. Dispersion
Answer» C. Refraction
Explanation: Refraction is the change in direction of wave propagation due to a change in its transmission medium. Due to the change of medium, the phase velocity of the wave is changed but its frequency remains constant.
515.

The mercury and sodium street lamps light up because of –

A. Atomic emission
B. Atomic absorption
C. Electron emission
D. Electron absorption
Answer» A. Atomic emission
Explanation: The light in sodium vapour lamp and mercury vapour lamp is, because of electron emission. In case of Sodium Lamps, filaments of the lamp sputter fast moving electrons, which hit the sodium atoms (vapour) causing the valence electrons of the sodium atoms to excite to higher energy levels and the electrons thus excited relax by emitting the characteristic monochromatic bright yellow light.
516.

Who invented the Lightning Rod in 1749?

A. Benjamin Franklin
B. Nikola Tesla
C. Eli Whitney
D. George Washington
Answer» A. Benjamin Franklin
Explanation: The principle of the lightning rod was first detailed by Benjamin Franklin in Pennsylvania in 1749. In the subsequent years, he developed his invention for household application (published in 1753) and further
517.

When the milk is churned vigorously the cream from it is separated out clue to –

A. Centripetal force
B. Gravitational force
C. Frictional force
D. Centrifugal force
Answer» D. Centrifugal force
Explanation: The separation of cream from milk is based on the fact that when liquids of different specific gravity revolve around the same centre at the same distance with the same velocity, a greater centrifugal force is exerted on the heavier liquid than on the lighter one. Milk consists of two liquids of different specific gravity: fat and milk serum.
518.

The temperature at which the catalytic activity of the catalyst is maximum, is called

A. room temperature
B. critical temperature
C. absolute temperature
D. optimum temperature
Answer» D. optimum temperature
Explanation: 0
519.

Which one of the following non-metals is not a poor conductor of electricity?

A. Sulphur
B. Selenium
C. Bromine
D. Phosphorus
Answer» B. Selenium
Explanation: Selenium is a non-metallic element; it is not a very good conductor of heat and electricity.
520.

Which instrument is used to record Atmospheric pressure?

A. Thermometer
B. Barometer
C. Seismometer
D. Oscilloscope
Answer» B. Barometer
Explanation: A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. A barometer using mercury is common. This is often recorded as mm Hg.
521.

Full form of CFL used in place of electric bulbs is –

A. compact fluorescent lamp
B. constantan filament lamp
C. closed filament lamp
D. closed fluorescent lamp
Answer» A. compact fluorescent lamp
Explanation: A compact fluorescent lamp (CFL) is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps.
522.

A light year is a unit of –

A. time
B. distance
C. speed of light
D. intensity of light
Answer» B. distance
Explanation: As defined by the International. Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year. It is a measure of distance (rather than, as is sometimes misunderstood, a measure of time).
523.

An instrument that records earth- quakes is –

A. Ergograph
B. Ediograph
C. Thermograph
D. Seismograph
Answer» D. Seismograph
Explanation: Earthquakes generate seismic waves which can be detected with a sensitive instrument called a seismograph. The earliestseismograph was invented in China A.D. 136 by a man named Choko.
524.

An object is in static equilibrium when it is               .

A. at rest
B. moving in a circular path
C. moving with uniform velocity
D. accelerating at high speed
Answer» A. at rest
Explanation: 0
525.

The study of phenomena at very low temperatures is called -

A. heat transfer
B. morphology
C. crystallography
D. cryogenics
Answer» D. cryogenics
Explanation: A person who studies elements that have been subjected to extremely cold temperatures is called a cryogenicist.
526.

Steel is more elastic than rubber because it –

A. requires larger deforming force
B. Is never deformed
C. is deformed very easily
D. is harder than rubber
Answer» C. is deformed very easily
Explanation: Elasticity is the capability of an object to return to its former shape once a load inducing strain is removed. Young Modulus or elastic modulus [tendency to be deformed elastically (i.e., nonpermanently) when a force is applied to it] of steel is more than that of rubber.
527.

Which phenomena shows the particle nature of light?

A. Diffraction
B. Interference
C. Photoelectric effect
D. Polarisation
Answer» C. Photoelectric effect
Explanation: The phenomena such as interference, diffraction, and polarization can only be explained when light is treated as a wave whereas photoelectric effect, line spectra, and the production and scattering of x rays demonstrate the particle nature of light.
528.

In the names Mangifera indica (mango), Solanum tuberosum (potato) and Panthera leo (lion), the terms Mangifera, Solanum and Panthera represent the higher level of?

A. Taxon
B. Taxonomic Hierarchy
C. Specific Epithet
D. Binomial Nomenclature
Answer» A. Taxon
Explanation: All the three names, indica, tuberosum and leo, represent the specific epithets while the first words Mangifera, Solanum and Panthera are genera and represents another higher level of taxon or category.
529.

Sound waves in air are             .

A. transverse
B. longitudinal
C. electromagnetic
D. polarised
Answer» B. longitudinal
Explanation: Sound can propagate through compressible media such as air, water and solids as longitudinal waves and also as a transverse wave in solids.
530.

The motion of a body that repeats itself after a regular interval of time is –

A. a periodic motion
B. a simple harmonic motion
C. an aperiodic motion
D. an oscillatory motion
Answer» A. a periodic motion
Explanation: The motion of a body that repeats itself after a regular interval of time is called 'Periodic Motion'. Simple Harmonic Motion is a type of periodic motion where the restoring force is directly proportional to the displacement.
531.

When a strong beam of light is passed through a colloidal solution, the light will –

A. be scattered
B. pass unchanged
C. be absorbed
D. be reflected
Answer» A. be scattered
Explanation: When a strong beam of light is passed through a colloidal solution, the light will be scattered.
532.

Which one of the following is not allied to Geophysical Sciences?

A. Hydrology
B. Meteorology
C. Palaeontology
D. Seismology
Answer» C. Palaeontology
Explanation: Palaeontology is the study of fossils and the evolution of life on Earth.
533.

The pitch of sound depends on its –

A. Frequency
B. Intensity
C. Velocity
D. Amplitude
Answer» A. Frequency
Explanation: Pitch is a perceptual property that allows the ordering of sounds on a frequency- related scale. Pitch may be quantified as a frequency, but pitch is not a purely objective physical property; it is a subjective psycho- acoustical attribute of sound.
534.

The ozone layer protects us from -

A. Ultra violet rays
B. Radio waves
C. Visual radiation
D. Infrared radiation
Answer» A. Ultra violet rays
Explanation: The ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (UVR) from the sun, protecting life on Earth from its potentially harmful effects.
535.

Entropy of the universe is -

A. continuously increasing
B. continuously decreasing
C. zero
D. constant
Answer» A. continuously increasing
Explanation: In an irreversible process, entropy always increases, so the change in entropy is positive. The total entropy of the universe is continually increasing.
536.

For which among the following house appliances, magnet is an essential part?

A. Calling bell
B. Fan
C. Washing machine
D. All of the above
Answer» D. All of the above
Explanation: 0
537.

Cylindrical lens is used by a person suffering from -

A. astigmatism
B. myopia
C. hypermetropia
D. None of these
Answer» A. astigmatism
Explanation: A cylindrical lens is typically used to focus, condense or expand incoming light. A cylindrical lens has one cylindrical surface, causing light to be focused in a single dimension or axis.
538.

Metals are good conductors of electricity because -

A. they contain free electrons
B. the atoms are lightly packed
C. they have high melting point
D. All of the above
Answer» A. they contain free electrons
Explanation: Copper is used for electrical wiring because it is a good conductor of electricity. Metal particles are held together by strong metallic bonds, which is why they have high melting and boiling points.
539.

Speed of sound in solids is -

A. 10 times that in gas/ 10
B. 20 times that in gas/ 20
C. 5 times that in gas/ 5
D. 15 times that in gas/ 15
Answer» D. 15 times that in gas/ 15
Explanation: Sound travels at 343 m/s in air; it travels at 1,480 m/s in water (4.3 times as fast as in air); and at 5,120 m/s in iron (about 15 times as fast as in air).
540.

To open a door easily, the handle should be fixed –

A. near the hinges
B. away from mid-point opposite to hinges
C. in the middle
D. None of these
Answer» D. None of these
Explanation: Since Torque = force x distance, to open a door easily, the handle should be fixed at the greatest distance from the hinges. If we pull with same force on a handle that is 2 feet away from the hinges, we will provide twice the torque, so it will be twice as easy to open.Q.50) Dioptere is the unit of –
541.

Velocity of sound in air does not depend on –

A. Density of air
B. Temperature of air
C. Pressure of air
D. Humidity of air
Answer» C. Pressure of air
Explanation: Assuming air to be an ideal gas, the speed of sound depends on temperature only. As air temperature increases, so does the speed of sound and vice versa. The speed of sound is completely independent of air pressure because the air pressure and air density are proportional to each other at the same temperature.
542.

Conversion of sound energy into electrical energy is done by –

A. Solar cell
B. Gramophone
C. Microphone
D. Loudspeaker
Answer» C. Microphone
Explanation: Conversion of sound energy into electrical energy is done by microphone.
543.

The theory of inheritance of acquired characters was propounded by -

A. Charles Darwin
B. Gregor Mendel
C. J. B. Lamarck
D. Weismann
Answer» C. J. B. Lamarck
Explanation: Lamarckism (or Lamarckian inheritance) is the hypothesis that an organism can pass on characteristics that it has acquired through use or disuse during its lifetime to its offspring.
544.

A jet engine works, on the principle of conservation of -

A. linear momentum
B. angular momentum
C. energy
D. mass
Answer» A. linear momentum
Explanation: Linear momentum is a vector quantity defined as the product of an object's mass, m, and its velocity, v. Linear momentum is denoted by the letter p and is called “momentum” for short: Note that a body's momentum is always in the same direction as its velocity vector.
545.

Which electromagnetic radiation is used for satellite communication?

A. Ultraviolet
B. Infrared
C. Microwave
D. Millimeter wave
Answer» C. Microwave
Explanation: Microwave electromagnetic radiation is used for satellite communication.
546.

Solar cells work on the principle of –

A. photovoltaic effect
B. photoelectric effect
C. photoconductive effect
D. photosynthesis
Answer» A. photovoltaic effect
Explanation: Solar cells work on the principle of photovoltaic effect.
547.

When a piece of stone is immersed in water, it displaces water of equal –

A. Density
B. Specific gravity
C. Mass
D. Volume
Answer» C. Mass
Explanation: Archimedes' Principle states that upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid the body displaces.
548.

Efficiency of the catalyst depends on its

A. physical state
B. amount used
C. molecular state
D. number of free valencies
Answer» C. molecular state
Explanation: 0
549.

The oil in the wick of lamp rises due to

A. Pressure difference
B. Pheonomenon of capillarity
C. Low viscosity of oil
D. Force of cohesion
Answer» B. Pheonomenon of capillarity
Explanation: The oil in the wick of lamp rises due to phenomenon of capillarity. This phenomenon is called molecular property of matter.
550.

Number of basic SI unit is               .

A. 4
B. 7
C. 6
D. 5
Answer» B. 7
Explanation: International System of Units (SI) is the modern metric system of measurement and the dominant system of international commerce and trade. It has seven base units.
551.

Optical fibre works on the -

A. principle of refraction
B. total internal reflection
C. scattering
D. interference
Answer» B. total internal reflection
Explanation: Optical fiber is a cylindrical dielectric waveguide (non-conducting waveguide) that transmits light along its axis, by the process of total internal reflection.
552.

Gas thermometers are more sensitive than the liquid thermometers because the gases –

A. have large coefficient of expansion
B. are lighter
C. have low specific heat
D. have high specific heat
Answer» A. have large coefficient of expansion
Explanation: Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the has thermometer is more sensitive than liquid (mercury) thereto-meter.
553.

A man standing on a edge of a cliff throws a stone vertically upwards with a certain speed. He then throws another stone downwards with the same speed. Find the ratio of the speeds of the two stones when they hit the ground.

A. 1 : 1
B. 1 : 2
C. 1 : 4
D. Cannot be found from the given information.
Answer» A. 1 : 1
Explanation: The stone which is throws upward will have the same velocity of u at the point of its original position when it is falling down. Another stone is thrown downwards with u. So the velocity of both the stones is equal at the original point. Hence both stone will hit theground with same velocity. So the ratio between the speeds of two stones will be 1:1
554.

The locomotion of insects to the source of light is called :

A. Phototropic
B. Hydrotropic
C. Phototactic
D. Thermotactic
Answer» A. Phototropic
Explanation: The growth or movement of a plant part in response to a source of light is called phototropism. It is most often observed in plants, but can also occur in other organisms such as fungi.
555.

The splitting of white light into its components is due to:

A. Reflection
B. Refraction
C. Transmission
D. Dispersion
Answer» D. Dispersion
Explanation: Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
556.

The moment of inertia of a body does not depend upon its –

A. axis of rotation
B. angular velocity
C. form of mass
D. distribution of mass
Answer» B. angular velocity
Explanation: Moment of inertia is the mass property of a rigid body that determines the torque needed for a desired angular acceleration about an axis of rotation. Moment of inertia depends on the shape of the body and the amount and distribution of its mass. It can be found through the sum of moments of inertia of the masses making up the whole object, under the same conditions.
557.

The speed of light will be minimum while passing through -

A. water
B. vaccum
C. air
D. glass
Answer» D. glass
Explanation: T Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0, but it slows down to 225,000 kilometers per second in water (refractive index = 1.3; see Figure 1) and 200,000 kilometers per second in glass (refractive index of 1.5).
558.

             is the cell organelle, in which the biochemical processes of respiration and energy production occur.

A. Mitochondria
B. Chloroplast
C. Ribosomes
D. Nucleus
Answer» A. Mitochondria
Explanation: Mitochondria is an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.
559.

Amount of water vapour in a unit volume (Cubic metre) of air is called:

A. Mixed ratio
B. relative humidity
C. absolute humidity
D. specific humidity
Answer» C. absolute humidity
Explanation: Absolute humidity is the measure of water vapor (moisture) in the air, regardless of temperature. It is expressed as grams of moisture per cubic meter of air (g/m3).
560.

Which waves cannot be transmitted through vacuum -

A. Light
B. Heat
C. Sound
D. Electromagnetic
Answer» C. Sound
Explanation: Sound waves cannot be transmitted through vacuum. It is transmitted by the movement of particles along with the direction of the motion of the sound wave. More generally, sound is a mechanical disturbance which is dependent upon a medium to travel.
561.

Super cooling stands for cooling of a liquid –

A. at freezing point
B. below freezing point
C. at melting point
D. above melting point
Answer» B. below freezing point
Explanation: Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid. A good example of this phenomenon is clouds in high altitude that are an accumulation of supercooled droplets of water below their freezing point. Refrigeration is a popular commercial application of supercooling.
562.

Alcohol is more volatile than water because              is lower than water.

A. its boiling point
B. its density
C. its viscosity
D. its surface tension
Answer» A. its boiling point
Explanation: Drinking alcohol (ethanol) and a lot of other simple alcohols are more volatile than water because they are less polar. Thus, alcohol has higher vapor pres-sure and a lower
563.

The boiling point of water depends upon the –

A. atmospheric pressure
B. volume
C. density
D. mass
Answer» A. atmospheric pressure
Explanation: The boiling point corresponds of water to the ternperature at which its vapour pressure equals the surrounding environmental pressure. So it is dependent on theatmospheric pressure. For example, at higher altitudes, the atmospheric pressure decreases. As this pressure decreases, the boiling point of the water also decreases.
564.

The loudness of sound depends upon

A. Velocity
B. Pitch
C. Amplitude
D. Wavelength
Answer» C. Amplitude
Explanation: Loudness is the characteristic of a sound that is primarily a psychological correlate of physical strength (amplitude).
565.

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
Explanation: Principle of conservation of linear momentum states If no external force acts on asystem of bodies, the total linear momentum of the system of bodies remains constant.
566.

Who among the following is the scalar quantity            .

A. force
B. pressure
C. velocity
D. acceleration
Answer» B. pressure
Explanation: Pressure is a scalar quantity. It relates the vector surface element with the normal force acting on it.
567.

When net torque is zero, will be constant -

A. force
B. angular momentum
C. linear momentum
D. acceleration
Answer» B. angular momentum
Explanation: Since a torque (rate of change of angular momentum analogous to force) applied over time is equivalent to a change in angular momentum, then if torque is zero, angular momentum is constant.
568.

Elecronegativity is the measure of -

A. Metallic character
B. Non-metallic character
C. Basic Character
D. None of these
Answer» B. Non-metallic character
Explanation: Electronegativity cannot be directly measured and must be calculated from other atomic or molecular properties. Several methods of calculation have been proposed, and although there may be small differences in the numerical values of the electro negativity, all methods show the same periodic trends between elements.
569.

Which of the following waves cannot be polarized?

A. Radio
B. Ultra violet
C. Infrared
D. Ultrasonic
Answer» D. Ultrasonic
Explanation: Only transverse waves (such as radio, ultraviolet and infrared waves) can be polarized since their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane.
570.

Which one of the following is a vector quantity?

A. Momentum
B. Pressure
C. Energy
D. Work
Answer» A. Momentum
Explanation: A vector quantity is a quantity that is fully described by both magnitude and direction.
571.

If the angle of incidence formed on a concave mirror at a point is 30° then the angle of reflection will be:

A. 15°
B. 30°
C. 60°
D. 90°
Answer» B. 30°
Explanation: The angle between the incident ray and the normal is known as the angle of inci dence. The angle between the reflected ray and the normal is known as the angle of reflection.
572.

Which among the following is not a unit of distance?

A. Light year
B. Longsec
C. Astronomical unit
D. Parsec
Answer» B. Longsec
Explanation: Longsec is unit of parse, parse is used to allocate distance to astronomical bodies beyond the solar system.
573.

The rotational effect of a force on a body about an axis of rotation is described in terms of the

A. Centre of gravity
B. Centripetal force
C. Centrifugal force
D. Moment of force
Answer» D. Moment of force
Explanation: The rotational effect of a force on a body about an axis of rotation is described in terms of the Moment of force.
574.

Radian per second is unit of               .

A. Momentum
B. Moment of Inertia
C. Frequency
D. Angle Velocity
Answer» D. Angle Velocity
Explanation: The SI unit of angular velocity is radians per second.
575.

Sound of frequency below 20 Hz is called             .

A. audio sounds
B. infrasonic
C. ultrasonic
D. supersonics
Answer» B. infrasonic
Explanation: The term "infrasonic" applied to sound refers to sound waves below the frequencies of audible sound and nominally includes anything under 20 Hz.
576.

Which among the following is not an inner planet?

A. Mercury
B. Saturn
C. Venus
D. Earth
Answer» B. Saturn
Explanation: The inner planets (in order of distance from the sun, closest to furthest) are Mercury. Venus, Earth and Mars.
577.

What is the phenomenon which established the transverse nature of light?

A. Reflection
B. Interference
C. Diffraction
D. Polarisation
Answer» D. Polarisation
Explanation: The phenomena which proves the transverse nature alight is polarization. Since the intensity of polarized light on passing through a tourmaline crystal changes, with the relative orientation of its crystallo-graphic axes with that of the polarizer, therefore light must consist of transverse waves. Transverse waves are waves that are oscillating perpendicularly to the direction of propagation
578.

During combustion of unsaturated compounds a              is seen.

A. clean flame
B. blue flame
C. red flame
D. yellow flame
Answer» D. yellow flame
Explanation: When saturated compounds are burnt in air,they give a clear(blue) flame due to complete combustion. However the burning of unsaturated compounds (alkenes and alkynes) gives a sooty (yellowish) flame due to incomplete combustion.
579.

Which one among the following doesn't have any effect on velocity of sound?

A. Pressure
B. Temperature
C. Humidity
D. Density
Answer» C. Humidity
Explanation: The speed of sound varies depending on the temperature, pressure, and density of the medium through which the sound waves travel. In most of the cases, it is density which matters. Sound travels faster through denser air (or other material). The density of air is affected by atmospheric pressure, temperature, and altitude.
580.

When a stone is thrown in the calm water of a pond the waves produced on the surface of water in the pond are –

A. longitudinal
B. transverse
C. both longitudinal and transverse
D. waves are not produced
Answer» B. transverse
Explanation: The waves produced on the surface of water in the pond is an example of transverse waves as particles of the medium do not move along with the wave. Only the disturbance is carried forward. Another example of such waves is the vibrations of a string.
581.

A cyclone is an engineering device that is used to -

A. transport materials
B. segregate particles
C. control switching devices
D. model fractals
Answer» B. segregate particles
Explanation: When removing particulate matter from liquid, a hydrocyclone issued; while from gas, a gas cyclone is used.
582.

The density of water is 1 g/cc. This is strictly valid at –

A. 0°C
B. 4°C
C. 25°C
D. 100°C
Answer» B. 4°C
Explanation: Water never has an absolute density because its density varies with temperature. Water has its maximum density of 1 g/cm3 at 4 degrees Celsius. When the temperature changes from either greater or less than 4 degrees, the density will become less than 1 g/cm3. Water has the maximum density of 1 g/cm3 only when it is pure water.
583.

Which of the following is one of the commercial products obtained from Gelidium and Gracilaria and are used to grow microbes and in preparations of ice- creams and jellies?

A. Agar
B. Chlorella
C. Spirullina
D. Gymnosperms
Answer» A. Agar
Explanation: Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies.
584.

In an electric motor, the energy transformation is from               .

A. electrical to chemical
B. chemical to light
C. mechanical to electrical
D. electrical to mechanical
Answer» D. electrical to mechanical
Explanation: An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this would be the conversion of mechanical energy intoelectrical energy and is done by an electric generator.
585.

A radioactive substance does not undergo any change (in mass or charge) during –

A. ganuna-emission
B. oxidation
C. alpha-emission
D. beta-emission
Answer» A. ganuna-emission
Explanation: Gamma-rays do not carry any charge. These rays do not have any mass and hence can not be considered to be made up of particles.
586.

On a rainy day, small oil films on water show brilliant colors. This is due to -

A. dispersion
B. interference
C. diffraction
D. polarization
Answer» B. interference
Explanation: The combination of two or more electromagnetic waveforms to form a resultant wave in which the displacement is either reinforced or cancelled.
587.

The waveform of a certain signal can be studied by –

A. Spectrometer
B. Cathode ray oscilloscope
C. p - n junction diode
D. Sonometer
Answer» D. Sonometer
Explanation: A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum. Cathode ray oscilloscope is an electronic display device containing cathoderay tube (CRT) that generates an electron beam that is used to produce visible patterns or graphs on a phosphorescent screen.
588.

Ultrasonic waves are produced by making use of -

A. ferro magnetic material
B. ferri magnetic material
C. piezo electric material
D. pyro electrical material
Answer» C. piezo electric material
Explanation: In most applications, ultrasonic waves are generated by a transducer that includes a piezoelectric material (crystal) that converts electrical energy (electric current) to mechanical energy (sound waves).
589.

Least audible sound for most of the human ear is –

A. 10.0 μ bar
B. 0.0002 μ bar
C. 0.005 μ bar
D. 5.0 μ bar
Answer» B. 0.0002 μ bar
Explanation: Least audible sound for most of the human ear is 2 x 10-5 pascal. The generally accepted standard range of audible frequencies is 20 to 20,000 Hz.
590.

Amount of water vapour (gaseous) in a given volume of air (cubic metre) is known as:

A. Mixing ratio
B. Relative humidity
C. Absolute humidity
D. Specific humidity
Answer» C. Absolute humidity
Explanation: The relative humidity of air at a given temperature is the ratio of mass of water vapour actually present in a certain volume of air to the mass of water vapour required to saturate the same volume of air at the same temperature, multiplied by 100.
591.

Which of the following is a conductor of electricity?

A. Rubber
B. Pure water
C. Salt water
D. Benzene
Answer» C. Salt water
Explanation: Pure water is actually an extremely poor conductor, but saturated salt water is a good conductor. The saltier the water, the better the conductance. The reason it conducts electricity is because the NaCl (sodium chloride) breaks apart into a positively charged Na+ and a negatively charged Chlorine CF. When current is applied, it is easily conducted by the highly charged ions.
592.

The opening and closing of the stomatal pores is a function of the -

A. Guard cells
B. Chloroplast
C. Xylem
D. Phloem
Answer» A. Guard cells
Explanation: The opening and closing of the pores is a function of the guard cells. They swell when water flows into them, causing the stomatal pore to open and likewise, the pore closes if the guard cells shrink.
593.

Which one among the following substances evolved heat when dissolved in water?

A. Glucose
B. Fructose
C. Quick lime
D. Salt peter
Answer» C. Quick lime
Explanation: Quicklime is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature.When limestone is heated, at about 1000° C it undergoes thermal decomposition.
594.

In the remote control of television, electromagnetic waves used are –

A. ultraviolet
B. microwave
C. radiowave
D. infrared
Answer» D. infrared
Explanation: All electromagnetic waves used are infrared.
595.

Heat flows as a result of difference of

A. Temperature
B. Density
C. mass
D. Volume
Answer» A. Temperature
Explanation: Heat flow moves energy from a higher temperature to a lower temperature. The bigger the difference in temperature between two objects, the faster heat flows between them.
596.

Sound and light waves both               .

A. have similar wavelength
B. obey the laws of reflection
C. travel as longitudinal waves
D. travel through vacuum
Answer» B. obey the laws of reflection
Explanation: The two laws of reflection of light are applicable to sound waves as well. The incident wave, the normal to the reflecting surface and the reflected wave at the point of incidence lie in the same plane.
597.

Radioactive elements can be traced out in living cell through a technique called –

A. Centrifugation
B. Chromatography
C. Auto radiography
D. All the above
Answer» C. Auto radiography
Explanation: Radioactive elements can be traced out in living cell through a technique called Autoradiography.
598.

Human beings can hear the sound range between:

A. 10 to 20 decibels
B. 100 to 150 decibels
C. 50 to 60 decibels
D. None of the above
Answer» D. None of the above
Explanation: The most accepted sound range of human being is 0 to 120 decibels.
599.

Solids which conduct electricity at higher temperature but not at lower temperature are called

A. super-conductor
B. metallic-conductor
C. semi-conductor
D. insulator
Answer» C. semi-conductor
Explanation: Semiconductors are insulators at low temperatures and reasonably good conductors at higher temperatures. As temperature increases, the semiconductor material becomes a better and better conductor.
600.

In a filament type light bulb most of the electric power consumed appears as –

A. visible light
B. infra-red rays
C. ultra-violet rays
D. fluorescent light
Answer» B. infra-red rays
Explanation: When electricity is passed through the filament, the filament gets hot. Depending on the temperature of the filament, radiation is emitted from the filament. The filament's temperature is very high, generally over 2,000°C. At this high temperature of 2,000°C, about 5 percent of the electrical energy converts into visible light and rest of it is emitted as heat or infrared radiation.
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