MPTET Varg 2 Science Mock Test - 3 - MPTET MCQ

दिए गए विकल्पों में से सही उत्तर विकल्प 3 'दुख-सुख' है। अन्य विकल्प इसके अनुचित उत्तर हैं। 

Key Points

• कांटे और कलियाँ 'दुख-सुख' की प्रतीक हैं। 
• कवि ने कहा कैसी भी परिस्थिति आए काबी व्यक्ति को दरकार झुकना नहीं चाहिए। 
• सुख और दुख तो आते जाते रहते हैं। 
• अन्य विकल्प अनुचित उत्तर हैं। 

Additional Information

• प्रतीक- आकृति या रूप 
• कलियाँ बहुवचन शब्द है इसका एकवचन रूप कली होता है। 
• कांटे का एकवचन रूप कांटा होगा। 

गद्यांश के अनुसार बाघ की प्रतिष्ठा अच्छी नहीं थी।

Key Points

• गद्यांश के अनुसार :
  • एक दिन बाघ ने एक जानवर को मार डाला, और उसे खाने के दौरान, उसके गले में एक छोटी हड्डी फंस गई। बाघ बहुत दर्द में था।
  • उसने रोना शुरू कर दिया और जंगल में प्रत्येक पक्षी और जानवर से हड्डी निकालने का अनुरोध किया।
  • लेकिन कोई भी उसकी मदद करने नहीं आया। अंत में उसने जो भी उसकी मदद करेगा उसके लिए इनाम की घोषणा की।
  • फिर भी कोई भी उसके पास आने की हिम्मत नहीं करता क्योंकि कोई भी उस पर भरोसा नहीं करता था।
  • वे जानते थे कि जैसे ही हड्डी बाहर निकाली जाएगी, वैसे ही खूंखार बाघ सहायक को मार देगा।
  • बाघ खुद को दुखी महसूस कर रहा था और मदद के लिए अनुरोध कर रहा था। आखिरकार, बाघ की दुखी स्थिति को देखकर, एक दयालु सारस ने उस पर दया की और कहा, "देखो, आपकी प्रतिष्ठा खराब है।

Additional Information

• बाघ का अर्थ - 
  • सिंह की जाति का एक हिंसक पशु। 
• बाघ का पर्यायवाची -
  • शार्दूल, सिंह, चीता, सर्वश्रेष्ठ, केसरी, पुंडरीक, अग्नि, तिलक, टीका, बहादुर आदि। 
• बाघ का स्त्रीलिंग शब्द -
  • बाघिन।
• बाघ का वैज्ञानिक नाम
  • "पेंथेरा टिग्रिस" है।
  • यह भारत का राष्ट्रीय प्राणी भी है।

Important Points

जंगल का कोई भी जानवर हड्डी निकालने में बाघ की मदद नहीं करना चाहता था क्योंकि वे उस पर विश्वास नहीं करते थे I

Key Points

• गद्यांश के अनुसार :-
  • एक दिन बाघ ने एक जानवर को मार डाला, और उसे खाने के दौरान, उसके गले में एक छोटी हड्डी फंस गई।
  • बाघ बहुत दर्द में था। उसने रोना शुरू कर दिया और जंगल में प्रत्येक पक्षी और जानवर से हड्डी निकालने का अनुरोध किया।
  • लेकिन कोई भी उसकी मदद करने नहीं आया। अंत में उसने जो भी उसकी मदद करेगा उसके लिए इनाम की घोषणा की।
  • फिर भी कोई भी उसके पास आने की हिम्मत नहीं करता क्योंकि कोई भी उस पर भरोसा नहीं करता था।
  • वे जानते थे कि जैसे ही हड्डी बाहर निकाली जाएगी, वैसे ही खूंखार बाघ सहायक को मार देगा।

Additional Information

• विश्वास का अर्थ -  
  • ​भरोसा 
• विश्वास का पर्यायवाची -
  • ऐतबार , यकीन , भरोसा , विश्वास , अक़ीदा , आश्वास , आस्था आदि 
• विश्वास का विलोम - 
  • ​अविश्वास ।
• विश्वास में उपसर्ग - 
  • "​वि"  है, श्वास मूल शब्द है 

Important Points

The correct answer is 'Because'.

Key Points         

• Because  is used for the reason that; since. 
• • ​For example: I was absent from school because I had a cold.
• Though means despite the fact that; although.
• Yet means but at the same time; but nevertheless.
• If means (introducing a conditional clause) on the condition or supposition that; in the event that.
• By referring to the above explanation and the context of the given sentence, it can be concluded that Because is the appropriate option to be chosen for filling the blank.

Hence, the correct answer is option 3.

Hinglish 

• "Because" का उपयोग 'क्योंकि' या ' जिसके कारण' के लिए किया जाता है। 
• "Though" का अर्थ होता है 'हालांकि' या 'फिर भी'।
• "Yet" का अर्थ होता है 'लेकिन फिर भी' या 'तथापि'।
• "If" का उपयोग शर्तीय वाक्यांश को परिचयित करने के लिए किया जाता है, जिसका अर्थ होता है 'यदि' या 'अगर'।

The correct answer is 'the.

Key Points 

• In English, there are three articles: a, an, and the.
• Articles are used before nouns or noun equivalents and are a type of adjective.
• The definite article (the) is used before a noun to indicate that the identity of the noun is known to the reader.
  • When we use the word 'Most' we use the article the.
• The indefinite article (a, an) is used before a noun that is general or when its identity is not known.
• There are certain situations in which a noun takes no article.
• In the given sentence, there is a use of the adjective 'most' hence article the will be used.

Hence, the correct answer is Option 2.

The correct answer is ‘Yoga for Humanity’.

Key Points

• The 8th edition of International Day of Yoga will be celebrated with the theme “Yoga for Humanity”.
• Ministry of Ayush has chosen this theme for the 8th International Day of Yoga 2022.
• It will be organised in India and across the globe on 21st June 2022.
• The theme of last year’s International Day of Yoga organised during the COVID-19 pandemic was “Yoga for wellness".

Additional Information

• ​The International Day of Yoga has been celebrated annually on 21 June since 2015, following its inception in the United Nations General Assembly in 2014.
• In 2015 Reserve Bank of India issued a 10 rupees commemorative coin to mark the International Day of Yoga.
• Minister of Ayush- Sarbananda Sonowal 

In the above series first number is subtracted from the square of natural numbers starting from 1 to form the next number:

Hence the correct answer is "60".

As per the given Venn diagram:

Here, '8' males are managers but not Engineers.

Hence, the correct answer is "Option (4)".

The correct answer is "Panna".

Key Points:

• 25th National Volleyball Championship was held at Talaiya Field Ground in Panna district of Madhya Pradesh.
• The event was inaugurated on 16 December.
• Position of teams In the men's category:
  • Gujarat- Winner.
  • Haryana- Runner up.
  • Karnataka- Third.
  • Uttar Pradesh- Fourth.
• Position of teams in the women's category:
  • West Bengal- Winner.
  • Rajasthan- Runner up.
  • Gujarat- Third.
  • Tamil Nadu- Fourth.
• The winning team was given a cash prize of Rs 51,000(For the Team) and Rs 3000 each

​ Important Points:

• Current President of the Volleyball Federation of India is Prof. Achyuta Samanta(Odisha).
• The Volleyball Federation of India was formed in the year 1951.
• First President of Volleyball Federation of India was Mr. F. C. Arora(Punjab).

Intelligence is referred to as the ability to perceive information and retain it as knowledge for applying it toward adaptive behaviors in the environment.

Key Points

• Intelligence tests are classified on several bases.
  •  Individual and Group tests (Target)
  •  Verbal and Nonverbal tests
• Performance tests are based n the performance of individuals.
• They are not paper pen tests and are based on the real performance of the students.
• They are prepared for children, deaf and dumb, and illiterates.

Hence we conclude that performance tests are useful for children, deaf and dumb, and illiterates. 
Additional Information

• Individual test- It is one that can be administered only to one person at a time (Simon-Binet).
• Group Tests - During World War I rapid and mass classification of army personnel was required and such tests could not fulfill these needs. So,  group intelligence tests were developed which could be administered to a group of individuals at one go (Army Alpha and Army Beta)

Kohler's Gestalt or Insightful Learning: According to gestalt psychology learning phenomenon is closely related to perception, and, therefore, they define learning as a reorganization of the learner's perceptual or psychological world. Gestalt Psychology uses the used the term 'insight' to describe the perception of the whole situation by the learner and his intelligence in responding to proper relationships.

Important Points

Gestalt theory of learning:

• It is primarily concerned with the nature of perception. According to it, an individual perceives the thing as a whole.
• A thing is perceived as a relationship within a field that includes the thing and its complex background incorporating their previous experiences and purposes.
• While learning, a learner always perceives the situation as a whole and after seeing and evaluating the different relationships intelligently takes a proper decision.
• The child first perceives the situation as a whole and then evaluates its parts that imply that they first learn anything as a whole and then learn their part.
• For example, children in their initial stage of learning, recognize all types of birds saying simply "birds" and afterward they start to distinguish between different types of birds i.e., sparrow, parrot, eagle, etc.

Key Points

His theory depends upon the following factors:

• Intelligence: Solutions depend upon the basic intelligence of the learner. The more intelligent the individual is the greater there will be his insight.
• Experience: Experience help in insightful solutions to problems.
• Learning Situations: Some situations are more favorable than others for insightful solutions.
• Repetition: After having an insightful solution to a particular type of problem, the individual tries to repeat it in another situation.

 Additional Information 

John B. Watson is known as the father of the school of psychology referred to as behaviorism.

Features of behaviorism

• It gave rise to new ideas and innovations in the field of learning.
• It helps in shaping the behavior of an individual.
• It helped in extending the scope of educational psychology.

Hence, we can conclude that meaningful perception of material is an essential component of learning. This is a concept of gestaltism.

Abraham Harold Maslow was an American psychologist, who was best known for creating the Hierarchy of Needs.

Key PointsThere is a number of theories and models of needs that have been proposed, one of them is Maslow’s hierarchy of needs.

Maslow’s hierarchy of needs is a theory in psychology, proposed by Abraham Maslow. Maslow’s hierarchy of needs is often portrayed in the shape of a pyramid, with the largest and lowest levels of needs at the bottom, and the need for self-actualization at the top. The five needs are as follows:-

• Physical\ physiological Needs: These needs pertain to the basic things necessary for survival that are hunger, thirst, shelter, etc. Human beings initially try to satisfy this need and once it is fulfilled, this need ceases to satisfy them. For example:- Food, Sleep, and Water.

• Security Needs: These needs talk about the job security or safety at the workplace that further provides a sense of psychological security to human beings. Maslow here talks about both physical and emotional safety and he opines that once the safety and security needs are ensured, they no longer motivate human beings.

• Social Needs: These needs represent the relationships between and among groups of people working in the organization. These needs provide emotional security to the people and also a sense of belongingness and association. Man is a social animal and likes to be friendly with others and if these needs are not met, the employee becomes resistant and hostile.

• Esteem needs:- These needs are those needs where human beings strive for power, achievement, and status. Esteem here denotes both self-esteem and esteem from others.

• Self-actualization need:- This need represents what we are capable of becoming, which would be our greatest achievement.

Thus, it is concluded that Food, Sleep, and Water are physiological needs, according to Maslow.

The correct answer is 22.5 J.

Important Points

• Work-energy theorem: It states that the sum of work done by all the forces acting on a body is equal to the change in the kinetic energy of the body i.e., Work done by all the forces = Kf - Ki
• 
  • Where v = final velocity, u = initial velocity and m = mass of the body

CALCULATION:

Given,

Mass (m) = 5 kg

Final Velocity (v) = 3 m/s 

Initial velocity (u) = 0 m/s

According to the work-energy theorem,

⇒  Work done = Change in K.E

⇒  W = Δ K.E

Since initial speed is zero so the initial KE will also be zero.

⇒  Work done (W) = Final K.E = 1/2 mv2

⇒  W = 1/2 × 5 × 3²

⇒  W = 45/2

⇒  W = 22.5 J

To prevent misuse of industrial ethanol, Methanol is added to it.

• To prevent the misuse of ethanol produced for industrial use, it is made unfit for drinking by adding poisonous substances like methanol to it.
• Dyes are also added to colour the alcohol blue so that it can be identified easily. This is called denatured alcohol.
• Denatured alcohol is used as solvent and fuel for burners of gasoline and camping stoves.
• Unlike the denaturation process in biochemistry, denaturing alcohol does not chemically change the ethanol molecule.

Science aims at enabling students to develop their communication skills to be able to understand scientific information, such as data, ideas, arguments, and investigations, and communicate it using appropriate scientific language in a variety of communication modes.

Key Points 

Scientific Attitude: Scientific attitude is caring about evidence and being willing to change theories on the basis of new evidence.

• The scientific attitude reveals why even a failed theory can help us to understand what is special about science.
• It is the grounding of science in evidence that offers a uniquely powerful tool in the defense of science.
• Scientific attitude helps to tackle problems objectively without bias promoting logical thinking.

The Characteristics of Scientific Attitude: 

• Scientific attitude refers to critical observation, inquisitiveness, broadmindedness, and open-mindedness.
• An individual is open-mindedness, curiosity, judgment based on verified facts, ready to test and verify conclusions, faith in cause and effect relationships, collecting and reporting scientific data, critical in observations, accepting no conclusions a final or ultimate, and more faith in the books written by specialists in their respective fields, etc.
• Scientific attitude includes the following habits of thinking, the habit of accuracy in all operations, have objectivity in approach to problems, including accuracy in calculation, observation, and report.
• Scientific attitude is the combination of many qualities and virtues, which is reflected through the behavior and action of the person. 

Hence, from the above-mentioned points, it becomes clear that Hard work is not a quality of scientific attitude.

This is correct answer is Both I and II.

Key Points

• Kilowatt-hour (kWh) and joules (J) are units of energy.

  1 kW = 1000 W

  1 watt(W) = 1 J/sec

  Therefore, 1 kW = 1000 J/sec

   And, 1 hour = 3600 sec

  So, 1 kWh = (1000 J/sc) × 3600 sec

  = 3.6 × 106 J.

• The SI unit of electric current is 'ampere'  (A) Ampere is a fundamental unit in the S.I system. The ampere is defined on the basis of the force acting between two current-carrying, parallel conductors.

• If Charge (Q) = 1 coulomb (C) , t = 1 second (s) ,  then i = 1 ampere (A) , thus

  1 ampere = 1 coulomb / second

  1A = 1 Cs^-1

Additional Information

• Electric current: The flow of charge in a conductor under a potential difference maintained between the ends of the conductor constitutes an 'electric current' in the conductor. In other words, The rate of flow of charge is called 'electric current.

• Thus, if in an electric circuit, an amount of charge Q flows in t second then the electric current (I) in the circuit is given by:

  I = Q/t

• We know that in metals the electric current is the flow of electrons. 1 electron carries 1.6 ×  10^-19 C of charge. Hence for 1 C of charge, 1/ (1.6 × 10^-19) = 6.25 × 10¹⁸ electrons should flow in 1 second.
• Thus 1 ampere = 6.25 × 10¹⁸ electrons per second.

The correct answer is option 2.

Key Points

• Given Reaction:
  • A + 2B → C.
  • This means 1 mole of A reacts with 2 moles of B to produce 1 mole of C.
  • No. of moles of B that react with 1 mole of A = 2. 
• According to question,
  • No. of moles of B present  = 8.
  • Therefore, 8 moles of B will react with 4 moles of A to form 4 moles of C.
  • 1 mole of A will remain unreacted after the consumption of 8 moles of B as B is the limiting reagent in the reaction.​

Hence 5 moles of A and 8 moles of B will produce 4 moles of C.

Important Points

• There must be at least two reactants for a reaction to take place.
• Sometimes reactions are carried out with amounts of reactants that are different than the amounts as required by a balanced chemical reaction.
• In such situations, one reactant is in a greater amount than the amount required by a balanced chemical reaction. 
• The reactant which is present in the least amount gets consumed after some time and after that further reaction does not take place whatever be the amount of the other reactant.
• Hence, the reactant, which gets consumed first, limits the amount of product formed called the limiting reagent.

Concept:

• Ecological pyramids are graphical representations of trophic systems in an ecosystem.
• Shape of pyramid can be upright (base broader than top), inverted (top broader than base) or variable.
• They are mainly of 3 types:

1. Pyramid of Number -
   • It is based on the number of individuals in each trophic level.
2. Pyramid of Biomass - 
   • It is based on the quantitative biomass of organisms present in unit area (standing crop), for each trophic level.
3. Pyramid of Energy -
   • It is based on the energy content available at each trophic level.

Important Points

• Trophic system refers to the system in which energy flows from one trophic level to another.
• Trophic level is the specific place in the food chain that is occupied by an organism based on their source of food.
• In an ecosystem, the trophic level starts with a producer and is succeeded by different levels of consumers.
• In an aquatic ecosystem like the sea, the usual food chain is like:

Phytoplankton → Zooplankton → Small fish → Big fish

• When we consider the quantitative biomass of each of the trophic levels, we find that the biomass produced by phytoplanktons is the minimum.
• Phytoplanktons are autotrophic planktons that act as producers for this ecosystem.
• As we gradually move up the trophic levels, we find the biomass to be increasing.
• The big fishes will have the maximum biomass in this ecosystem.

Therefore, ecological pyramid is generally inverted for a pyramid of biomass in a sea.

Additional Information

• Pyramid of numbers in grassland - Upright
• Pyramid of energy - Always upright
• Pyramid of biomass in a forest - Upright

Explanation:

⇒  Fe₂O₃ → Fe

It happens in 2 Stages:

a) Reduction

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

b) Slag formation

CaO + SiO₂ → CaSiO₃

Concept-

• The mechanism of muscle contraction is best explained by the sliding filament theory.
• It states that the contraction of a muscle fiber takes place by the sliding of the thin filaments over the thick filaments.

Explanation-

• A characteristic feature of the muscle fibre is the presence of a large number of parallelly arranged filaments in the sarcoplasm called myofilaments or myofibrils.
• Each myofibril has alternate dark and light bands on it.
  •     The light band is called an I-band or Isotropic band and contains only actin filament.
  • The dark band is called an Anisotropic or A-band contains Myosin and Actin.
  • Z-line is present between I-band.
  • H-zone is the middle portion of the A-band which carries only myosin.

    The area between two Z-line is Sarcomere and It is considered as the functional unit of contraction and is called a sarcomere.

Additional Information

• Study of muscles known as Myology.
• Almost all muscles of the body develop from the mesoderm.

Concept:

Photochemical Smog

• Photochemical smog is found to be a mixture of pollutants that are formed when nitrogen oxide and volatile organic compounds react with sunlight thereby creating a brown haze.
• This photochemical smog is the major contributor to air pollution. 
• It develops when the primary pollutants (chemicals from fossil fuel combustion) interact with sunlight to produce a mixture of hazardous chemicals known as secondary pollutants.

Explanation:

Primary pollutants

• The two major primary pollutants are nitrogen oxides and volatile organic compounds.
• These primary pollutants combine react with sunlight and create secondary pollutants. 

Secondary pollutants

• Secondary pollutants are ozone, peroxyacetyl nitrate (PAN). 

Among the given compounds CFCs is not a common component of Photochemical smog. 

CFCs ( chlorofluorocarbon) is a man-made compound, containing chlorine, fluorine and carbon. The most common emitter of CFCs is refrigerants.

The correct answer is Silk farming.

Key Points

• Sericulture is the production of raw silk by means of raising caterpillars (larvae).
• Bombyx mori is the most widely used and intensively studied silkworm for Silk farming.
• China and India are the leading producers of silk with more than 60% of the world's annual production.
• Silk is a fiber made up of proteins namely sericin and fibroin.

Additional Information

• Pisciculture is the scientific rearing and management of all fish farming.
• Apiculture is the scientific rearing of honey bees for the commercial production of honey and other bee products.
• Horticulture is related to fruit production
• Sylviculture is related to the cultivation of fodder crops
• Olericulture is related to the cultivation of vegetables.

Concept:

• Organisms need a constant supply of nutrients to grow, reproduce and regulate various body functions. The amount of nutrients, such as carbon, nitrogen, phosphorus, calcium, etc., present in the soil at any given time, is referred to as the standing state. It varies in different kinds of ecosystems and also on a seasonal basis.
• Nutrients are never lost from the ecosystems, rather they are recycled time and again indefinitely. The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling.
• Another name of nutrient cycling is biogeochemical cycles (bio: living organism, geo rocks, air, water).
• Nutrient cycles are of two types
• Gaseous- the reservoir for the gaseous type of nutrient cycle (e.g., nitrogen, carbon cycle) exists in the atmosphere
• Sedimentary- for the sedimentary cycle (e.g., sulfur and phosphorus cycle), the reservoir is located in Earth‟s crust.
• Environmental factors, e.g., soil, moisture, pH, temperature, etc., regulate the rate of release of nutrients into the atmosphere. The function of the reservoir is to meet the deficit which occurs due to an imbalance in the rate of influx and efflux.

Explanation:

• The sulphur reservoir is in the soil and sediments where it is locked in organic (coal, oil and peat) and inorganic deposits (pyrite rock and sulphur rock) in the form of sulphates, sulphides and organic sulphur.
• It is released by weathering of rocks, erosional runoff and decomposition of organic matter and is carried to terrestrial and aquatic ecosystems in a salt solution.
• The sulphur cycle is mostly sedimentary except two of its compounds hydrogen sulphide (H2S) and sulphur dioxide (SO2) add a gaseous component to its normal sedimentary cycle.
• Sulphur enters the atmosphere from several sources like volcanic eruptions, combustion of fossil fuels, from the surface of the ocean and from gases released by decomposition. Atmospheric hydrogen sulphide also gets oxidised into sulphur dioxide.
• Atmospheric sulphur dioxide is carried back to the earth after being dissolved in rainwater as weak sulphuric acid.

Additional Information

• Carbon is a minor constituent of the atmosphere as compared to oxygen and nitrogen. However, without carbon dioxide life could not exist, because it is vital for the production of carbohydrates through photosynthesis by plants. It is the element that anchors all organic substances from coal and oil to DNA (deoxyribonucleic acid the compound that carries genetic information).
• Carbon is present in the atmosphere, mainly in the form of carbon dioxide (CO₂). The carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals. By process of respiration and decomposition of dead organic matter returns back to the atmosphere. It is usually a short term cycle.
• Some carbon also enters a long term cycle. It accumulates as un-decomposed organic matter in the peaty layers of marshy soil or as insoluble carbonates in bottom sediments of aquatic systems which take a long time to be released.
• In deep oceans, such carbon can remain buried for millions of years till geological movement may lift these rocks above sea level. These rocks may be exposed to erosion, releasing their carbon dioxide, carbonates and bicarbonates into streams and rivers.
• Fossil fuels such as coals, oil and natural gas etc. are organic compounds that were buried before they could be decomposed and were subsequently transformed by time and geological processes into fossil fuels. When they are burned the carbon stored in them is released back into the atmosphere as carbon dioxide.

• Nitrogen is an essential constituent of protein and is a basic building block of all living tissue. It constitutes nearly 16% by weight of all the proteins that is, converted to ammonia, nitrites or nitrates before it can be taken up by plants.
• Nitrogen fixation on earth is accomplished in three different ways:
  a) By microorganisms (bacteria and blue-green algae)
  b) By man using industrial processes (fertilizer factories) and
  c) To a limited extent by atmospheric phenomena such as thunder and lighting
• Certain microorganisms are capable of fixing atmospheric nitrogen into ammonium ions. These include free-living nitrifying bacteria (e.g. aerobic Azotobacter and anaerobic Clostridium) and symbiotic nitrifying bacteria living in association with leguminous plants and symbiotic bacteria living in non-leguminous root nodule plants (e.g. Rhizobium) as well as blue-green algae (e.g. Anabaena, Spirulina).
• Ammonium ions can be directly taken up as a source of nitrogen by some plants, or are oxidized to nitrites or nitrates by two groups of specialised bacteria: Nitrosomonas bacteria promote the transformation of ammonia into nitrite. Nitrite is then further transformed into nitrate by the bacteria Nitrobacter.
• The nitrates synthesised by bacteria in the soil are taken up by plants and converted into amino acids, which are the building blocks of proteins. These then go through higher trophic levels of the ecosystem. During excretion and upon the death of all organisms nitrogen is returned to the soil in the form of ammonia.
• Certain quantities of soil nitrates, being highly soluble in water, are lost to the system by being transported away by surface run-off or groundwater. In the soil as well as oceans there are special denitrifying bacteria (e.g. Pseudomonas), which convert the nitrates/nitrites to elemental nitrogen. This nitrogen escapes into the atmosphere, thus completing the cycle.
• The periodic thunderstorms convert the gaseous nitrogen in the atmosphere to ammonia and nitrates which eventually reach the earth’s surface through precipitation and then into the soil to be utilized by plants.

Hydrogen Cycle-

• The hydrologic cycle is the continuous circulation of water in the Earth-atmosphere system which is driven by solar energy. Water on our planet is stored in major reservoirs like the atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater. Water moves from one reservoir to another by the processes of evaporation, transpiration, condensation, precipitation, deposition, runoff, infiltration, and groundwater flow.
• Water as an important ecological factor determines the structure and function of the ecosystem. Cycling of all other nutrients is also dependent upon water as it provides their transportation during the various steps. It acts as a solvent medium for their uptake of nutrients by organisms.

Explanation:

The burning of pop sound signifies the Presence of hydrogen. 

• When Zinc metal is kept in HCl, a chemical reaction takes place. The reaction is:

Zn + dil. HCl → ZnCl2 + H2

• The observations will be:
  • A colourless odourless gas is evolved.
  • The colour of the salt changed to white.
• The gas evolved is Hydrogen, and it burns with a 'pop' sound.

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• The salt colour changes to white due to the formation of Zinc Chloride, which is white in colour.
• So, the correct option is Acid metal reaction. 

Additional Information

• The burning of magnesium forms magnesium powder which is white in colour. 
• Acid-base reactions form salt and water. The reaction is known as the neutralisation reaction.
• The formation of slaked lime (Ca(OH)₂) from quick lime (CaO) is an exothermic reaction and do not form any gas. 

The correct answer is Water that is behind a dam.

Key Points

•  Gravitational Potential-
  • It is the work done per unit mass in a gravitational field that is equivalent to the work done by some externally applied force to bring a massive object to that point from some defined position of zero potential. 
  • It is a scalar quantity.
• Gravitational potential energy is the energy an object possesses because of its position in a gravitational field.
• The water behind a hydroelectric dam stores gravitational potential energy since it is at a higher level than the water on the other side of the dam.
• As the waterfalls, this potential energy is converted into kinetic energy, which turns turbines to generate electricity.

The correct answer is 76 cm of Hg.
Key Points

• Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth.
• The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa), which is equivalent to 1013.25 millibars, 760 mm Hg, (or 76 cm Hg) 29.9212 inches Hg, or 14.696 psi.
• The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.

Additional Information
Temperature Conversion Formula Table

Gypsum is an ore of Calcium (Ca). The chemical formula of Gypsum is CaSO₄.2H₂O

• Gypsum is mainly used as a fertilizer, as the main constituent in plaster, chalk, etc.
• Rapid setting of cement is the function of gypsum in cement.
• It is a crystalline mineral composed of calcium sulfate dihydrate.
• Gypsum helps in controlling the rate of hardening of the cement.
• It also prevents early hardening allowing long working time, hence we can say that it helps in the rapid setting of cement.
• The Bikaner district of Rajasthan has the maximum quantity of Gypsum.
• Rajasthan produces 90% of total production in India.

Additional Information

Some common chemical compounds with their common names are:

• The phenolphthalein in acidic solution is Colourless.
• HPh (Unionised, Colourless)  [ H⁺ + Ph^– ] (Ionised, Pink).
• Phenolphthalein is a weak acid.
• It does not dissociate in the acidic medium and remains in the unionised form.
• The unionised form is colourless and hence, phenolphthalein in acidic solution is Colourless.
• In the alkaline medium, the ionisation of phenolphthalein increases considerably.
• There is constant removal of H+ ions released from HPh by the OH– ions from the alkali.
• So the concentration of Ph– ion increases in the solution, which imparts pink colour to the solution.
• Hence, phenolphthalein in the presence of bases, turn pink.

The correct answer is Scattering.

Key Points

• Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air.
  • Blue light is scattered more than the other colours because it travels as shorter, smaller waves.
  • This is why we see a blue sky most of the time.

Additional Information

•  The sky is blue due to a phenomenon called Raleigh scattering.
  • This scattering refers to the scattering of electromagnetic radiation (of which light is a form) by particles of a much smaller wavelength.
  • Scattering affects the colour of light coming from the sky, but the details are determined by the wavelength of the light and the size of the particle.
  • Our eyes are more sensitive to blue rather than violet this means to us the sky appears blue.

The correct answer is option 3.

Key Points

Conductivity:

• Conductivity refers to the ability of a material to transmit energy.
• There are different types of conductivity, including electrical, thermal, and acoustical conductivity.

Electrical Conductivity:

• Electrical conductivity is nothing but the measure of the capability of the material to pass the flow of electric current.
• Electrical conductivity differs from one material to another depending on the ability to let the electricity flow through them.
• Protons, electrons, and neutrons present in the material carry the current. Protons carry a positive charge and each electron has a negative charge that it carries with it wherever it goes.
• The flow of electrons inside the material is referred to as the electric current. 
• The most electrically conductive element is silver, followed by copper and gold. Hence option 3 is correct.
• Silver also has the highest thermal conductivity of any element and the highest light reflectance.
• Electrical conductivity is denoted by the Greek letter ρ.
• The  Electrical conductivity is the inverse of the resistivity and is given by
  • σ = 1/ρ, Where, σ = electrical conductivity, ρ = resistivity.
• SI units: Siemens per meter [S/m]