RRB/RRC Level 1 Posts MCQ 2019 EXAM
 |
| RRB NTPC MCQ 2019 |
Q1. The material used in the fabrication of a transistor is .
A Aluminum
B Copper
C Silicon
D Silver
Ans - C
The fabrication of the transistor is the process of creating the transistor that is used in electrical and electronics circuit. Transistors are made from very pure silicon or germanium, but certain other semiconductor materials can also be used.
Q2. In which of the following processes is energy released?
A Respiration
B Photosynthesis
C Ingestion
D Absorption
Ans A Respiration is the process in which energy is realeased .
Q3. The technique of collecting information about an object from a distance without making physical contact with it is
A Remote sensing
B Remote control
C Remote accessing
D Space Shuttleg.
Ans A Remote sensing
Q4. “Curie” is the unit of
A Radioactivity
B Temperature
C Heat
D Energy
Ans A.
.The Curie (symbol Ci) is a non-SI unit of radioactivity.
Q5. The Source of the sun’s energy, is the process of
A Photoelectric emission
B Nuclear fission
C Nuclear fusion
D Thermionic emission
Ans C
Sol. Sun generates its energy by nuclear fusion of hydrogen nuclei into helium.
Q6. It is difficult to walk on any oily floor because
A Floor gets spoiled
B There is more resistance
C Force of friction is high
D Force of friction is very less
Ans D
Sol. It is difficult to walk on oily surface because the surface has less friction. We can walk only if there is more friction. So we slip easily thus it is hard to walk on an oily floor.
Q7. The coefficient of static friction is
A Less than the coefficient of kinetic friction
B Greater than the coefficient of limiting friction
C Equal to coefficient of kinetic friction
D Equal to the tangent of the angle of friction
Ans D.
Sol. The angle which the resultant of the limiting friction and the normal reaction which makes the normal reaction is called the angle of friction. But the tangent of the angle of friction is equal to the coefficient of static friction.
Q8. A matchstick struck on a matchbox catches fire easily because
A Friction may cause fire
B of chemical reaction
C Force heated the match stick
D None of the above
Ans A
Sol. A matchstick is a small stick of wood with a solidified mixture of flammable chemicals deposited on one end.When that end is struck on the side of the matchbox which is a rough surface the friction generates enough heat to ignite the chemicals and produce a small flame
Q9. Tyres are treaded to
A To look good
B Increase friction
C To increase its longevity
D To increase weight of the tyre
Ans b tyre are treaded to increase friction.
Q10. Lubricants are substances which
A Increases friction
B Are used to light fire
C Reduces friction
D Are used to put off fire
Ans C lubricant is subtance which decrease friction
Q11.A compass needle cannot be used to detect
A Magnetic North-South direction
B Polarity of a magnet
C Strength of a magnet
D Direction of magnetic field
Ans C compass needle can not use to detect strength of magnet
rrb mcq , ntpc
Q12. Indicate the false statement about the resistance of a wire
A It depend on material of wire
B It is unrectly proportional to the length of wire
C It is directly proportional to the area of cross-section of wire
D Resistance of metallic wire increases with increase in temperature
Ans C
Sol. The resistance of a current carrying conductor is inversely proportional to the area of cross section of the conductor. The reason is because the resistance occurs due to the collision of electrons/charged particles.So resistance is inversely proportional to area of cross section of the conductor.
Q13.For which of the following substances, the resistance decreases with increase in temperature?
A Pure silicon
B Copper
C Nichrome
D Platinum
Ans A
Sol. Pure Silicon at room temperature has perhaps one conduction electron for every 1013 (that’s ten trillion) atoms. Increasing the temperature of intrinsic semiconductors provides more thermal energy for electrons to absorb, and thus will increase the number of conduction electrons. Voila – decreased resistance.
NTPC EXAM RRB
Q14. The ratio of intensity of magnetisation to the magnetisation force is known as
A flux density
B susceptibility
C relative permeability
D none of the above
Ans B
electromagnatism the magnetic susceptibility is one measure of magnetic
properties of a material . The susceptibilty indicated whether a material is attracted
into or repelled out of a magnetic field .
Q15. When a bar magnet is cut into two equal halves, the pole strength of each piece
A Becomes double
B Becomes half
C Becomes zero
D Remains the same
Ans D
Sol. When a bar magnet is cut into two equal halves, the pole strength of each piece Remains the same.
Q16. White light is made up of seven colors. What is the method of separating the
colors?
A By passing it through a prism
B By filtration
C Can’t be separated
D Both (a) and (b)
Ans A
Sol. The speed of light and its components vary inversely with the refractive index of the medium. Refraction is the deviation in the path of light when it travels from one optical medium to the other. Different wavelengths experience different degree of deviation. As a result, white light splits into 7 colours (VIBGYOR) on passing through the prism.
Q17. Retina of the eye is comparable to which of the following parts of a traditional
camera?
A Film
B Lens
C Shutter
D Cover
Ans A
Sol. Retina of the eye is comparable to the film of a traditional camera. Retina is a film of nerve fibres. Image of the object is formed at retina just like camera film is used to see the images.
Q18. The filament of an electric bulb is made of
A copper
B Aluminum
C lead
D tungsten
Ans D
Sol. Filament of bulb is made of tungsten because of its high melting point (3422°C), lowest vapour pressure and great tensile strength. Hence, when current passes, it gets heated to emit light but does not melt or expand
Q19. Which mirror is used as a rear view mirror in the vehicles?
A Plane
B Convex
C Concave
D Plano concave
Ans B
Sol. Convex mirror is a diverging mirror used as a rear view mirror in the vehicles as it covers wide range of vehicles coming behind.
Q20. The reason of mirage is
A Interference of light
B Diffraction of light
C Polarization of light
D Total internal reflection of light
Ans D
Sol. Mirage is an optical illusion. The reason of mirage is total internal reflection of light.
In summer air near the ground is hotter and hence rarer than the air above which is responsible for TIR, hence, mirage is formed.
Q21.Energy used in solar cookers, solar distillation plants, solar power plants is known as
A Chemical energy
B Solar energy
C Thermal energy
D Nuclear energy
ANS B
Sol. Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis.
NTPC EXAM RRB
Q22. One horse power is equal to
A 790 watts
B 700 watts
C 720 watts
D 746 watts
ANS D
Sol. A power level of 1 hp is approximately equivalent to 746 watt s (W).
Q23. When a body falls freely under gravity, then the work done by the gravity is
A Positive
B Negative
C Zero
D Infinity
ANS A
Sol. If a force acting on a body has a component in the direction of displacement, then the work done by the force is positive. Hence when a body falls freely under the influence of gravity the work done by the gravity is positive.
Q24. When a body slides against a rough horizontal surface, the work done by friction is
A Positive
B Zero
C Negative
D Constant
ANS C
Sol. If a force acting on a body has a component in the opposite direction of displacement, the work done is negative, when a body slides against a rough horizontal surface, its displacement is opposite to that of the force of friction. He works done by the friction is negative.
Q25. Energy possessed by a body due to its stationary is called its
A heat energy
B kinetic energy
C potential energy
D chemical energy
ANS C
Q26.The Doppler’s effect is applicable for
A light wave
B sound wave
C space wave
D both (a) and (b)
ANS D
Sol. The Doppler effect can be observed to occur with all types of waves – most notably water waves, sound waves, and light waves. That was the Doppler effect – a shift in the apparent frequency for a sound wave produced by a moving source.
Q27.If a sound travels from air to water, the quantity that remain unchanged is
A velocity
B frequency
C wavelength
D amplitude
ANS B
Sol. If a sound travels from air to water, the quantity that remain unchanged is frequency.
Q28.Waves which do not require any material medium for its propagation is
A Matter waves
B Mechanical waves
C Elastic waves
D Electromagnetic waves
ANS D
Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.
Q29.Sound travels fastest in
A steel
B air
C water
D vacuum
ANS A
Sol. The speed of sound depends on the medium in which it is transported. Sound travels fastest through solids, slower through liquids and slowest through gases.
Q30.Beats occur because of
A interference
B reflection
C refraction
D doppler effect
ANS A
Sol. A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.
NTPC EXAM RRB
Q31.The types of waves produced in a sonometer wire are
A longitudinal stationary
B transverse stationary
C longitudinal progressive
D None of these
ANS B
Sol. If the vibrations of the particles are perpendicular to the propagation of the wave, those waves are said to be transverse waves. Waves produced in a sonometer wire is transverse stationary wave.
Q32. An α-particle consists of which of the following?
A 2 protons and 2 neutrons
B 1 proton and 1 electron
C 2 protons and 4 neutrons
D 1 proton and 1 neutron
ANS A
Sol. An α-particle is identical with helium nuclei. It consists of 2 protons and 2 neutrons .
Q33. Which one of the following substances is made from natural raw materials?
A Rayon
B Nylon
C Polyester
D Polystyrene
ANS A
Sol. Rayon is made from naturally occurring cellulose. Rayon is also called artificial silk.
Q36. Which one of the following metals is less reactive than hydrogen?
A Barium
B Copper
C Lead
D Magnesium
ANS B
Q37. What is the purpose of adding baking soda to dough?
A To generate moisture
B To give a good flavor
C To give good color
D To generate carbon dioxide
ANS D
Sol. Baking soda has sodium bicarbonate as the chief constituent. It decomposes on heating giving carbon dioxide. This causes dough, cakes, biscuits etc. to expand and become light.
Q38. As which one of the following, does carbon occur in its purest form in nature?
A Graphite
B Coal
C Diamond
D None of These
ANS C
Sol. Diamond occurs in its purest form of carbon black in nature.
Q39. In a car battery, electrolyte substance used is-
A Hydrochloric acid
B Sulphuric acid
C Nitric acid
D Distilled water
ANS B
Sol. Electrolyte substance used in a car battery is Sulphuric acid (H_2 SO_4 ). It is a strong acid.
Q40. The energy, found in dry cell is
A Mechanic
B Electric
C Chemical
D Electromagnetic
ANS C
Sol. The best example of changing into electric energy from chemical energy is primary cells or batteries, the dry cell is also made up in this phenomenon.
NTPC EXAM RRB
Q41. A pungent smell often present near the urinals is due to-
A Sulphur-di-oxide
B Chlorine
C Ammonia
D Urea
ANS C
Sol. Urine odour is caused by the presence of Ammonia. Urine is an aqueous solution of greater than 95% water.
Q42. Which chemical substance is used for making rat poison?
A Ethyl Alcohol
B Methyl Isocyanate
C Potassium Cyanide
D Ethyl Isocyanide
ANS C
Sol. Potassium Cyanide (KCN) or Zinc Phosphide is a highly toxic chemical used as a rodenticide a poison to kill the mouse.
Q43. Which gas is used in fire extinguisher?
A Carbon dioxide
B Hydrogen
C Oxygen
D Sulphur dioxide
ANS A
Sol. Carbon dioxide gas is used in a fire extinguisher to control small fires, often in emergency situations.
Q44. Which one of the following is used in the manufacture of soaps?
A Vegetable oil
B Mobil oil
C Kerosene oil
D Cutting oil
ANS A
Sol. Soap is a combination of animal fat or plant oil and caustic soda. Many vegetable fats including olive oil, palm kernel oil and coconut oil are also used in soap making.
Q45. Blue litmus paper is converted into red in solution of–
A Acid
B Base
C Alkali
D Salt
ANS A
Sol. Blue litmus paper turns red under acidic conditions.
Q46. Red litmus paper is changed into blue in solution of–
_
A Base
B Acid
C Salt
D None
ANS A
Sol. Red litmus paper turns blue under basic conditions.
Q47. In neutralisation reaction product is
A Acid
B Base
C Salt & Water
D None
ANS C
Sol. A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7.
Q48. Breath analysers used by police to test drunken drivers works on the chemical basis of
A Redox reactions
B Acid-base reactions
C Precipitation reactions
D complexation reaction
ANS B
Sol. Breath analysers used by police to test drunken drivers works on the chemical basis of Acid-base reactions.
Q49. The negative logarithmic value of hydrogen ion is called
A PH
B POH
C pKa
D pKb
ANS A
Sol. The logarithm of the hydrogen ion concentration in a solution, with the sign changed from positive to negative, is called the pH.
Q50. The vertical lines in modern periodic table are called
A Period
B Group
C Non-metal
D None
ANS B
Sol. The vertical columns of elements are called groups.
Q51. The horizontal line in modern periodic table is called–
A Period
B Group
C metal
D None
ANS A
NTPC EXAM RRB
Sol. In the periodic table of elements, there are seven horizontal rows of elements called periods.
Q52. Alkali metals are in a group
A II A
B VII A
C I A
D III A
ANS C
Sol. The group 1 of the periodic table contain six elements namely Lithium(Li), Sodium(Na),Potassium(K),Rubidium(Rb),Cesium(Cs) and Francium(Fr).These metals are called alkali metals because they form alkalies.
Q53. The elements in group zero are called
A Alkali metals
B Transition metals
C Inert gases
D None
ANS C
Sol. The noble gases are the elements in Group 0 (sometimes called Group 8) in the Periodic Table: helium, neon, argon, krypton, xenon, and radon.
Q54. Aluminium is diagonally related to
A Li
B Be
C C
D B
ANS B
Sol. Diagonal Relationship Of Beryllium and Aluminium. Beryllium shows resemblance with its diagonally opposite element aluminium.
NTPC EXAM RRB
Q55.Cathode rays have –
A mass only
B charge only
C no mass and no charge
D mass and charge both
ANS D
a cathode ray is a beam of electrons and electrons have mass and charge
Q56.Neutron was discovered by
A J.J. Thomson
B Chadwick
C Rutherford
D Priestley
ANS B
Sol. Neutron was discovered by James Chadwick. Sir James Chadwick was a British physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
Q57.The discovery of neutron became very late because
A it is present in nucleus/
B it is fundamental particle
C it does not move
D it does not carry any
ANS D
Sol. The discovery of neutron became very late because it does not carry any charge.
Q58.The three basic components of an atom are
A Protons, neutrons and ions
B Protons, neutrons and electrons
C Protium, deuterium and tritium
D Protons, neutrinos and ions
ANS B
Sol. The three main parts of a atom is protons, neutrons and electrons. Protons – have a positive charge, located in the nucleus, Protons and neutrons have nearly the same mass while electrons are much less massive. Neutrons- Have a negative charge, located in the nucleus.
Q59.The word ‘insolation’ means
A Matters which insulates
B Incoming solar radiation
C Insoluble matters
D None
ANS B
Sol. The amount of solar radiation reaching a given area.
Q60.Which of the properties of the element is a whole number?
A atomic weight/
B atomic number
C atomic radius
D atomic volume
ANS B
Sol. The property of elements which is always a whole number is its atomic number i.e. the number of protons and electrons.
Q61.Neutrino has
A charge +1, mass 1
B charge 0, mass 0
C charge -1, mass 1
D charge 0, mass 1
ANS B
Sol.A neutrino is a subatomic particle that is very similar to an electron, but has no electrical charge and a very small mass, which might even be zero.
Q62. What is Vermiculture?
A The science of raising worms
B The science of studying animals
C The science of studying fishes
D The science of killing worms
ANS A
Sol. Vermiculture is the process of managing and cultivating earthworms. Earthworms can help turning organic waste into nutrient-rich soil for your garden.
Q63. The study of Gerontology, is related to which of the following?
A Child infant
B Female
C Disease of skin
D Old age
ANS D
Sol. The scientific study of old age, the process of aging and the particular problems of old people is called Gerontology.
Q64. Genetics deals with
A Mendel’s laws
B Organic evolution
C DNA structure
D Heredity and variations
ANS D
Sol. Genetics is the study of genes, heredity and genetic variation in living organisms
Q65. Dinosaurs were:
A Cenozoic reptiles
B Mesozoic birds
C Paleozoic amphibians
D Mesozoic reptiles
ANS D
Sol. The Mesozoic Era is the age of the dinosaurs and lasted almost 180 million years from approximately 250 to 65 million years ago. This era includes three well known periods, called the Triassic, Jurassic and Cretaceous periods.
Q66. Poison gland of snakes is homologous to
A Electric organ of fishes
B Stings of rays
C Sebaceous glands of mammal
D Salivary gland of vertebrates
ANS D
Sol. Poison gland of snakes is homologous to salivary glands of vertebrates. Snake venom is actually the refined from of its saliva
Q67. Desert plants are generally
A Viviparous
B Succulent
C Herbaceous
D Heterophyllous
ANS B
Sol. A succulent is a plant that stores water for times when water is not available to it. Succulent plants are generally found in arid environments such as deserts and semi-deserts.
Q69. Contraction of heart is also known as
A Systole
B Aristotle
C Diastole
D Lub
ANS A
Sol. Diastole is that part of the cardiac cycle during which the heart refills with blood after the emptying done during systole which is also known as contraction.
Q70. Azadirachta indica is the botanical name of which of the following?
A Rose plant
B Apple tree
C Neem
D Mango
ANS C
Sol. Azadirachta indica is botanical name of neem. It is a multipurpose tree that is highly popular in India, where it provides food and insecticide, and is used for its great number of ethnomedicinal properties.
Q71. Which of the following is the main end product of carbohydrate digestion?
A Fats
B Lipids
C Glucose
D Cellulose
ANS C
Sol. End products of digestion of carbohydrates are Glucose, fructose and galactose
Q72. Which of the following glands is a source of the enzyme Ptyalin?
A Pancreas
B Thyroid Gland
C Pituitary Gland
D Salivary Glands
ANS D
Sol. Salivary gland is a source of enzyme Ptyalin. The enzyme ptyalin ,or salivary amylase acts on starches and converts them to maltose. It helps in the predigestion of starches.
Q73. Which of the following is not true about Pteridophyta?
A Dominant phase is sporophytes
B Main plant body is diploid
C Seeds are present
D Flowers are absent
SOL C
Sol. Pteridophyte are vascular plants i.e., plants with xylem and phloem, that reproduce and disperse via spores. They are seedless, vascular cryptogams.
Q74. The largest dolphin species is the orca, also called as _
A Bottle Nose
B Baiji
C Killer whale
D Tucuxi
ANS C
Sol. Orcas dolphin is also known as killer whales are the largest member of the dolphin family
Q75. The mulberry fruit is
A Sorosis
B Syconus
C Samara
D Nut
ANS A
Sol. The mulberry fruit is also known as the Sorosis. Sorosis is a multiple fleshy fruits that is derived from the ovaries of multiple flowers. The seeds are achenes, on the outside of a fleshy fruit. Pineapple and Ficus are also the example of Sorosis fruit.
Q76. Which one of the following groups of organisms has significance in diagnosing the death by drowning?
A Lichens
B Protozoa
C Cyanobacteria
D Diatoms
ANS D
Sol. Diatoms are useful in forensic studies. It has significance in diagnosing the death by drowning. Diatoms are photosynthetic algae and are found in almost every aquatic environment including fresh and marine waters, soils and almost at every humid place.
Q77. Leg-haemoglobin is found in
A Human blood
B Rabbit blood
C Legume root nodules
D Chicken blood
ANS C
Sol. Leg-haemoglobin is found in root nodules of leguminous plants such as alfalfa and soyabean.
Q78. Desert plants are generally-
A Viviparous
B Succulent
C Herbaceous
D Heterophyllous
ANS B
Sol. A succulent is a plant that stores water for times when water is not available to it. Succulent plants are generally found in arid environments such as deserts and semi-deserts.
Q79. A group of archaebacteria is used in the production of
A Ethane
B Methane
C Acids
D Alchohols
ANS B
Sol. Archaebacteria sub-kingdom of the kingdom Prokaryote, which on the basis of both RNA and DNA. Archaebacteria have unique protein-like cell walls and cell membrane simple organic compounds such as methanol and acetate as food, combining them with carbon dioxide and hydrogen gas from the air and releasing methane as a byproduct.
Q80.Biologists have so far known, found and identified a large number of species in the plant and animal kingdom. In terms of numbers, the largest found and identified so far is from among the
A Fungi
B Plants
C Insects
D Bacteria
ANS C
Sol. Biologists scientifically estimated the number of arthropod species. About 10 million accounts for over 80% of all known living animal species. All insects belong to the group ‘Insecta’ which is a class of phylum Arthropoda. Class Insects represents the largest number of world species.
Q81. Warm-blooded animals are those which are able to keep their body temperature
A Lower than environment
B Higher than environment
C Constant temperature all time
D Equal to the atmospheric temperature
ANS C
Sol. Warm-blooded creatures like mammals and birds are able to keep their bodies at a constant temperature. They do this by generating their own heat when they are in a cooler environment and by cooling themselves in a hotter environment. This process of maintaining a consistent environment inside the body is called homeostasis.
Q82. Which is the largest organ in human beings?
A Skin
B Large Intestine
C Small Intestine
D Liver
ANS A
Sol. The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold.
Q83. Of the following which one is not a fish ?
A Starfish
B Sawfish
C Pipefish
D Guitarfish
ANS A
Sol. Starfish popularly called sea stars are related to the phylum Echinodermata while true fishes belong to the phylum Chordata. Starfish do not have gills, scales or fins which are basic characteristics of fishes.
Q84. Which of the following vitamins contain cobalt-
A Vitamin B6
B Vitamin B2
C Vitamin B1
D Vitamin B12
ANS D
Sol. Vitamin B12 (Cyanocobalamin) is a water soluble vitamin. It contains a metallic ion cobalt.
Q85. Thiamine is:
A Vitamin C
B Vitamin B2
C Vitamin B6
D Vitamin B1
ANS D
Sol. Thiamine (Vitamin B1) is a water-soluble vitamin that is necessary for carbohydrate and amino acid metabolism.
Q86. What are vitamins?
A Organic compound
B Inorganic compound
C Living organism
D None of these
ANS A
Sol. Vitamins are organic compounds and a vital nutrient that an organism requires in limited amounts.
Q87. Itai-Itai disease is caused by chronic poisoning of-
A Mercury
B Nickel
C Cadmium
D Lead
ANS C
Sol. Itai-Itai disease is caused by prolonged poisoning of cadmium. The first documented occurrence of mass cadmium poisoning in the world occurred in 1950 in Toyama Prefecture in Japan. However, for the first time, the disease was reported in 1912.
Q88. Deficiency of which vitamin can cause night blindness?
A B1
B C
C A
D E
ANS C
Sol. Vitamin A is needed by the retina of the eye in the form of retinol, which combines with protein opsin to form rhodopsin, the light absorbing molecules necessary for both low light (scotopic vision) & colour vision.
Q89. The source of Vitamin ‘D’ is
A Lemon
B Sun rays
C Orange
D Cashewnut
ANS B
Sol. The source of Vitamin D is sun rays. In fact, vitamin D is synthesized in our dermal cell by sun rays which is released in the blood. Besides of sun ray, Vitamin D is obtained from butter, the yolk of egg, liver, and kidney, etc. Rickets in children and osteomalacia in adults occur due to deficiency of Vitamin D. Together with Calcium deficiency of vitamin D causes osteoporosis in older adults.
Q90. Water soluble vitamin is
A Vitamin A
B Vitamin C
C Vitamin D
D Vitamin E
ANS B
Sol. Vitamin B and C are water soluble vitamins whereas A, D, E and K are fat-soluble Vitamins.
Q91. Vitamin ‘C’ help in absorption of which of following elements?
A Iron
B Calcium
C Iodine
D Sodium
ANS A
Sol. Vitamin C is helpful in iron absorption whereas vitamin D helps in absorption of magnesium and calcium.
Q92. Which one of following hormones stimulates pancreas for the production of digestive juice?
A Rennin
B Trypsin
C Secretin
D Pepsin
ANS C
Sol. Secretin is a hormone that stimulates pancreas for the production of digestive juice. Secretin also helps to regulate the pH of the duodenum by inhibiting the secretion of gastric acid from the parietal cells of the stomach. It also stimulates the contraction of the pancreas.
Q93. Yeast is an example of
A Bacteria
B Fungus
C Virus
D Algae
ANS B
Sol .Yeasts, molds and mushrooms are example of fungi.
Q94. Which of the following is a source of bio-fertilizer?
A Yeast
B Chlorella
C Azolla
D Mold
ANS C
Sol. Azolla has the capability of nitrogen-fixing. That is way it is being widely used as a bio-fertilizer, especially in parts of southeast Asia.
Q95. A fan produces feeling of comfort during hot weather, because
A fan supplies cool air
B Pulse code modulation
C Frequency modulation
D Time dimension multiplication
ANS C
Sol. Television broadcasts emit two types of signals, audio and visual. These two signals require modulation to transmit both signals at the same time. Analog television requires transmission that uses specific modulation methods employing AM and FM signals in its transmission. Frequency modulation or FM is used for the audio part of the transmission. Amplitude modulation or AM is used in the video transmission.
Q96. Bats can fly during dark nights and also prey. This is because
A The pupil of their eyes is large
B Their night vision is very good
C Every bird can do this
D They produce ultrasonic waves and are guided by them
ANS D
Sol. Bats are fascinating group animals. They are one of the few mammals that can use ultrasonic sound to navigate. As they fly, make an ultrasonic (shouting) sound. The returning echoes give the bats information about anything that is ahead of them, including the speed and size of an insect and which way it is going. This system of finding prey is called echolocation-locating things by their echoes.
Q97. The gas used for artificial fruit ripening of green fruit is
A Ethylene
B Acetylene
C Ethane
D Methane
ANS A
Sol. Ethylene can promote ripening in tomatoes,bananas, citrus, pineapples, dates, persimmons,pears, apples, melons, mangos, avocados, papayas and jujubes – a clear indication that the action of ethylene is general and widespread amongst a number of fruits. It is clear that ethylene is a ripening hormone – a chemical substance produced by fruits with the specific biological phenomenon of accelerating the normal process of fruit maturation and senescence.
Q98. The three elements most needed in common fertilisers are
A Sulphur, Phosphorous and sodium
B Nitrogen, Potassium and Phosphorous
C Phosphorous, Sodium and Nitrogen
D Calcium, Phosphorous and Potassium
ANS B
Sol. Fertilizer (or fertiliser) is any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to the growth of plants. The three elements most needed in common fertilisers are Nitrogen. Potassium and Phosphorous
Q99. Which one of the following metals pollutes the air of a city having large number of automobiles?
A Cadmium
B Chromium
C Lead
D Copper
ANS C
Sol. The history of car pollution has been one of air and water contamination followed by regulated improvement. Cars and trucks cause a lot of air the pollution in the world today, and contribute a lot to the most common and dangerous air pollutants. About 2.3 million tons of lead in lead acid (PbA) batteries is on the road now. Over 1 million tons of lead is used in making new batteries each year. In the past, motor vehicles were the biggest source of lead. But since leaded gasoline has been phased out, lead emissions have decreased by about 98 percent. Today, metal processing is the biggest source of atmospheric lead. The highest air concentrations are found in the vicinity of ferrous and nonferrous smelters and battery manufacturers.
Q100. An atomic pile is used for
A producing X-rays
B conducting nuclear fission
C coducting thermonuclear fusion
D accelerating atoms
ANS B
Sol An atomic pile is a nuclear reactor that uses controlled nuclear fission to generate energy. The most common reactor consists of a large assembly of graphite (an allotropic form of carbon) blocks having rods of uranium metal (fuel).
Good questions very helpful for ntpc rrb exam
ReplyDeletethank you
DeleteThis comment has been removed by the author.
ReplyDelete