NDA General Ability Test 17 April 2016 Official Paper (Previous Year Paper)

The correct answer is "inevitable"

Key Points

• Look at the meaning of the selected word**:**
• Inevitable: Something which can not be avoided.
• Look at the example:
• We can't escape death, it's inevitable.
• Look at the meanings of the rest of the words:
• Undeniable: Unable to deny or disputed.
• Fatal: Something that causes death.
• Miserable: Sorrowful
• Since the bus was at full speed and then its brakes failed, as a result, there was a very high probability of the bus meeting with an accident. In other words, under the mentioned circumstances, the accident was unavoidable or inevitable.

Hence the correct sentence: When the bus was at full speed, its brakes failed and an accident was inevitable.

Hinglish

• Inevitable- जिसको टाला न जा सके
• Fatal- जिससे मौत हो जाती है
• Miserable- दुखी
• undeniable- जिसको मना न किये जा सकते

The correct answer is option 3, i.e. Sketched.

Explanation 

• An architect is a person who designs buildings. Here, it is mentioned that the architect used the blackboard to explain his designs to the visitors. The appropriate verb for the noun 'design' is 'sketch'. So, sketched is the most suitable answer.

• One must not get confused with 'built'. Built is generally used for any construction work. Here, the word 'design' is used. So, on the blackboard, the sketches are drawn.

The correct answer is option 3) i.e. perfected.

Explanation

• Cultivated means well refined, educated.
• Finished means completed.
• Perfected means make something flawless, faultless.
• Enlarged means made larger in size.
  

As per the context of the given sentence, Bonsai was originated in China, but it was made perfect in its characteristics by the Japanese. So, all the other three options are not fit to be used in the sentence.

The correct answer is option 4) i.e. decorous.

Explanation:

• Decrepit means worn out because of age or neglegency, infirm, weak.
• Decadent means reflecting a state of moral or cultural decline.
• Decorative means relating to decoration, attractive.
• Decorous means having good taste, polite, restrained.
  

Important Point:

• Clearly, option 1 and 2 are giving out negative meanings and the context of the sentence is positive. So, the first two options are ruled out.
• The behaviour of a person can not be decorative since the word 'behaviour' is an abstract noun and can not be touched but only felt. Whereas, attractive is used for physical beauty. So, decorous, which means polite is the correct answer.
  

Mistake point:

• One must not get confused between the words decorous and decorative. Read the important points for the difference between these two words.

The correct answer is option 3) i.e. explaining.

Explanation

• Since the sentence talks of a trouble, which is to be explained to the principal. The only correct and suitable answer will be 'explaining'.

• Explain means give a reason so as to justify an event. The context of the sentence is the same. The principal needs a justification about the problem and not just that he be informed about the occurrence of a trouble. Therefore, saying is not suitable here.
  

• Please note that interrogative sentences mentioning 'mind' is always followed by a gerund (Here, explaining). The first form of the verb, here, explain, would be grammatically wrong.

The correct answer is 'to'.

Key Points

• Immune means "free, exempt" or "protected from" in general use, and "resistant to a disease" in common medical use.
• When immune is in context with any disease, the fixed preposition 'to' is used with immune.
• If you are immune to something, it generally has no effect on you, for example, you might be immune to a disease or to criticism. 
• Example: Most people who have had chickenpox once are immune to it for the rest of their lives.
• ​Therefore, the most appropriate option to be filled in the given blank is 'to'.
• Hence, option 2 is the correct answer.

Complete sentence: Vaccination will make people immune to certain diseases for a given period.

Additional Information

• Let's explore the given options:
• 'Against' means as protection or defense from the bad effects of.
• 'To' is used after many verbs of agreeing, needing, and wanting.
• 'With' is used to say that people or things are in a place together or are doing something together.
• 'For' means intended to be given to.

Hinglish

• Immune का अर्थ है "मुक्त, छूट" या सामान्य उपयोग में "संरक्षित", और सामान्य चिकित्सा उपयोग में "बीमारी के लिए प्रतिरोधी"।
• Immune के साथ प्रयोग किया जाने वाला निश्चित preposition, जब प्रतिरक्षा किसी रोग के संदर्भ में हो, 'to' है।
• यदि आप किसी चीज से immune हैं, तो आमतौर पर इसका आप पर कोई प्रभाव नहीं पड़ता है, उदाहरण के लिए, आप किसी बीमारी या आलोचना के प्रति प्रतिरक्षित हो सकते हैं।
• उदाहरण: Most people who have had chickenpox once are immune to it for the rest of their lives.
• अत: दिए गए रिक्त स्थान की पूर्ति के लिए सर्वाधिक उपयुक्त विकल्प 'to' है।
• अतः विकल्प 2 सही उत्तर है।
• आइए दिए गए विकल्पों का पता लगाएं:
• 'Against' का अर्थ है के बुरे प्रभावों से सुरक्षा या बचाव।
• सहमत, आवश्यकता और चाहने की कई क्रियाओं के बाद 'to' का प्रयोग किया जाता है।
• 'With' का प्रयोग यह कहने के लिए किया जाता है कि लोग या चीजें एक जगह पर हैं या एक साथ कुछ कर रहे हैं।
• 'For' का अर्थ है देने का इरादा।

पूर्ण वाक्य: Vaccination will make people immune to certain diseases for a given period.

The correct answer is option 3) i.e. distinguish.

Explanation

• Discriminate means make an unjust or prejudicial distinction in the treatment of different categories of people.
• Discern means to recognize or find out.
• Distinguish means to recognize or treat as different.
• Identify means to recognize or point out something.

• Discriminate provides a negative meaning, therefore, it is ruled out as per the context of the sentence. Discern, Distinguish, and identify mean the very same thing. But for the use of the preposition 'between', the only suitable option is 'distinguish'. As among the given options only 'distinguish' is always followed by the preposition 'between'.

The correct answer is option 3) i.e. pitched.

Explanation:

• Dug means made a hole by breaking up and moving earth.
• Installed means place or fix equipment or machinery in position ready for use.
• Established means having existed or done something for a long time and therefore recognized and generally accepted.
• Pitched in context of a tent means setting up of a tent.

Important Point:

• From the above explanations, we can say that only Pitched is the correct option to use in the sentence. Since tent is not machinery, so it can not be installed. Nor it can be set inside the earth, therefore, dug is also ruled out. Also, tent is a temporary stay, so it is not set very long time ago, therefore, established too cannot be used. Whereas, pitch is used specially for setting up of tents.

The correct answer is option 1) i.e. divulge.

Explanation

• Divert means draw the attention of someone from something, to turn from one direction to another.
• Indulge means involve oneself in some sort of pleasure.
• Invert means put something in the opposite position.
• Divulge means make known private or sensitive information.
• As evident from the context of the sentence, a person was captured by the enemy, even though the captured person's life was at stake, he did not reveal any personal or secret information to the enemy. From the words explained, only divulge fits contextually to the sentence.

The correct answer is option 4) i.e. clumsy.

Explanation

• Deft means skillful.
• Delicate means fragile, easily breakable.
• Sturdy means strongly built.
• Quick means fast.
• Clumsy means awkward or unskillful.
  

From the above explanations, we can clearly determine that Clumsy is the correct answer.

The correct answer is option 2) i.e. rude.

Explanation

• Urbane means polite or courteous in behavior.
• Rural means places that are far away from cities.
• Irrational means not reasonable.
• Indifferent means having no interest or Unconcerned.
• Rude means bad mannered or impolite.
• Since the meaning of Urbane is courteous or polite, its opposite word is Rude.

• One must not get confused between Urbane and Urban. Urban means characteristics of a town or city, whereas Urbane means polite.

The correct answer is 'boldness'.

Key Points

• The word 'Timidity' means lack of courage or confidence. (साहस या आत्मविश्वास की कमी)
• ​Let's see the meaning of other given options:-
• 'Arrogance' means the quality of being arrogant. (घमंडी, अभिमानी)
• 'Boldness' means fearless before danger or showing a fearless daring spirit. (साहस, निडरता और आत्‍मविश्‍वास)
• 'Skillfulness' means accomplished with skill. (कुशलता से संपन्न)
• 'Cunning' means clever in a dishonest or bad way. (बेईमान या बुरे तरीके से चतुर, चालाक)
  

Hence, the correct answer is option 2.

Additional Information

• The antonyms of the word 'Timidity' are "boldness, courage, confidence".
• The synonyms of the word 'Timidity' are "fear, panic, anxiety".
• Example of 'Boldness' in a sentence:
• He is famous for the boldness of his business methods.

The correct answer is option 2) i.e. Small.

Explanation:

• Mammoth means enormous, gigantic, very large in size.
• Significant means noteworthy, important.
• Unruly means disorderly.
• Noisy means involving a lot of noise.
• Small means insignificant or unimportant.
• As per the above explanation, mammoth and small are opposite in meaning to each other.
  

Important point:

• Mammoth and significant are synonyms to each other as evident from the above explanation.

The correct answer is 'inattentive'.

Key Points

• The word 'Engrossed' means so interested in something that you give it all your attention. (किसी चीज में इतनी दिलचस्पी कि आप उस पर अपना ��ूरा ध्यान दें)
• ​Let's see the meaning of other given options:-
• 'Occupied' means busy doing something. (किसी काम में व्‍यस्‍त)
• 'Inattentive' means not paying attention to something. (किसी चीज पर ध्यान नहीं देना)
• 'Engaged' means busy doing something. (किसी कार्य में व्‍यस्‍त)
• 'Absent' means showing that you are not really looking at or thinking about what is happening around you. (कहीं और ध्यान होना)
  

Hence, the correct answer is option 2.

Additional Information

• The antonyms of the word 'Engrossed' are "inattentive, absent, distracted".
• The synonyms of the word 'Engrossed' are "engaged, interested, involved".
• Example of 'Inattentive' in a sentence:
• An inattentive driver can do serious damage at very slow speeds.

The correct answer is 'following'.

Key Points

• The word 'Preceding' means coming before something in order, position, or time. (क्रम, स्थिति या समय में किसी चीज से पहले आना)
• ​Let's see the meaning of other given options:-
• 'Following' means to come, go or happen after somebody or something. (किसी व्‍यक्ति या वस्‍तु के पीछे आना, जाना या होना)
• 'Previous' means coming or happening before or earlier. (किसी से पहले या जल्‍दी आने या होने वाला; पूर्व)
• 'First' means before any others. (सबसे पहले)
• 'Last' means at the end; after all the others. (अंतिम; सबके बाद, अंत में)
  

Hence, the correct answer is option 1.

Additional Information

• The antonyms of the word 'Preceding' are "following, after, later".
• The synonyms of the word 'Preceding' are "foregoing, previous, prior".
• Example of 'Following' in a sentence:
• The hunter is following up a wolf.

The correct answer is option 2) i.e. Wild.

Explanation:

• Shrewd means having or showing sharp powers of judgement; astute.
• Clever means wise, astute.
• Incorrect means not in accordance with fact; wrong.
• Discriminating means showing good judgement.
• Wild means casual (In the context of the question).
• Since Shrewd and discriminating mean Astute or clever, its opposite will be wild, i.e. casual. 
  

Important point:

• We often say it is my wild guess. we mean by this that our guess is not supported by any logic or fact but even though we are expressing it. It can be correct or incorrect. Therefore, Wild does not mean that this will always be incorrect, so option 3 is ruled out.

The correct answer is 'mild'.

Key Points

• The word 'Severe' means (of something bad or undesirable) very great; intense.  (गंभीर, तीव्र, सख़्त)
• ​Let's see the meaning of other given options:-
• 'Violent' means very strong and impossible to control. (प्रचंड और बेक़ाबू)
• 'Mild' means not strong; not very bad. (नरम; हलका)
• 'Bad' means not good; unpleasant. (बुरा, ख़राब, अप्रिय)
• 'Continuous' means happening or existing without stopping. (बिना रुके होने वाला; लगातार)
  

Hence, the correct answer is option 2.

Additional Information

• The antonyms of the word 'Severe' are "mild, gentle, tender".
• The synonyms of the word 'Severe' are "rough, rugged, ungentle".
• Example of 'Mild' in a sentence:
• We had an exceptionally mild winter last year.

The correct answer is option 1) i.e. individually.

Explanation  

• Cumulatively means taken as a whole or taken in combination.
• Obviously means in a way that is easily perceived or understood; clearly.
• Clearly means easily understood.
• Collectively means as a group or as a whole.
• Individually means personally; in an individual capacity.
• As per the above explanation, obviously and clearly can not be the antonyms of cumulatively. Also, collectively and cumulatively are synonyms to each other. Thus, we are left only with individually, which is opposite in meaning to the word Cumulatively, as per the above explanation.

The correct answer is option 4) i.e. Unnoticeable.

Explanation:

• Conspicuous means attracting notice or attention, clearly visible.
• Charming means very pleasant or attractive.
• Ugly means unpleasant.
• Small means insignificant.
• Unnoticeable means not easily observed or noticed.
• As per the above explanation, conspicuous means something which is clearly visible. The only word opposite in meaning will be Unnoticeable.

Origin - mid 16th century: from Latin conspicuus (from conspicere ‘look at attentively’, from con- (expressing intensive force) + spicere ‘look at’) + -ous.

The correct answer is 'occasional'.

Key Points

• The word 'Continual' means something happening again and again. (बारंबार होने वाला, लगातार, निंरतर)
• ​Let's see the meaning of other given options:-
• 'Repeated' means something done or happening many times. (अनेक बार किया जाने या होने वाला; पुनरावृत्त)
• 'Irrational' means not based on reason or clear thought. (जो तर्क या स्‍पष्‍ट चिंतन पर आधारित न हो)
• 'Occasional' means something done or happening from time to time but not very often. (कभी-कभार किया जाने या होने वाला)
• 'Regular' means something done or happening often. (प्रायः किया जाने या घटित होते रहने वाला)
  

Hence, the correct answer is option 3.

Additional Information

• The antonyms of the word 'Continual' are "occasional, irregular, alternating".
• The synonyms of the word 'Continual' are "repeated, regular, continuous".
• Example of 'Occasional' in a sentence:
• The weather was good except for an occasional shower.

The correct answer is option 1) i.e. A.

Explanation:

• It is incorrect to use '-ing' form of verb with 'understand'. The correct form is 'understood'.
• 'Understand' is a non- continuous verb. So, it can not be used in the progressive form. Non-continuous verbs; verbs that cannot be used in continuous forms are usually verbs that you cannot see somebody doing. Other such verbs are want, need, etc.
  

Mistake point:

• Never use these continuous verbs, i.e.  wanting, needing, understanding. As these form of the verbs do not exist.

The correct answer is option 4) i.e. D.

Explanation:

• The given sentence is correct. 'On account of' means 'because of'.
• The meaning of the sentence is after all the houses of the village were washed away by the floods, the villagers stayed in the panchayat office.
• There is no error in the subject and verb. The villagers (plural subject) is followed by sought (plural verb). So, the sentence is errorless.

The correct answer is option 1) i.e. A.

Explanation

• Let us break the sentence into two parts and examine. 'It is necessary for us to familiarize with the way of the people...' & 'It is necessary for us to get used to the way of the people...'. The first part of the sentence should use a reflexive pronoun (Here, ourselves) after familiarize. The correct form will be, 'It is necessary for us to familiarize ourselves with the way of the people...' Here, the second part of the sentence is correct.

• Reflexive pronouns are words ending in -self or -selves that are used when the subject and the object of a sentence are the same (e.g., I believe in myself).

• Also, the use of 'among' is grammatically correct because 'To live among (someone) means':  To spend a portion of one's life as an outsider within an established community.

The correct answer is option 2) i.e. B.

Explanation:

• In indirect speech, the formation of the sentence would not be interrogative, i.e. use helping verb or a main verb ( here, 'cried') after the subject (here, 'she') in reported speech. So, write 'why she cried out' in place of 'why did she cry out'.
• The correct form is: The mother asked the child why she cried out in her sleep.

The correct answer is option 1) i.e. A.

Explanation 

• Remove 'that' used before 'why'. Because in indirect sentences, we never use conjunction ( Here, 'that') before wh-word (Here, 'why')  when reported verb 'asked' is used in indirect sentences. Here, Wh-word ('Why') is already being used as a conjunction.
• The correct form of the sentence is: I asked him why he was angry but he did not answer.

The correct answer is option 4) i.e. D.

Explanation:

• The sentence is correct. 'Taken ill' means 'to suddenly become ill'. Also, the third form of the verb, i.e. 'taken' is used with 'had'. It is absolutely correct.
• Also, if the sentences use imaginary conditions phrases such as 'If I', 'Had I', then use, 'would + helping verb + Third form of the verb (V₃)' in the secondary clause of the sentence, ( here used as 'would have sent you..'). Therefore, the given sentence is correct in all aspects.

The correct answer is option 4) i.e. D.

Explanation 

• The given sentence is grammatically correct. 'Helps' is used here for the subject 'The barn owl', which is a singular subject and so is the verb 'helps'.

• In later part if the sentence, verb 'do' is used for the 'rats' which is plural, and so is the verb 'do'. Therefore, the sentence is correct in all aspects of grammar.

• Aspirants should not get confused that the verb 'do',i.e. plural verb, is used here for ' the barn owl'. It is not so. 'Do' is used here for 'rats', i.e. plural subject.

The correct answer is option 3) i.e. C.

Explanation:

• The given sentence should be in the past perfect tense, as evident from the uses of 'three weeks ago'. But the later part of the sentence uses present perfect tense,i.e. 'has'. For a sentence to be grammatically correct, all parts of a sentence should be in one type of tense. So, replace with, 'he had not come yet'.

Mistake point:

• Aspirants very often overlook this type of error, i.e. use of different type of tense in single sentence,(parallelism) as done in this question. Refer to explanation above for better understanding.

The correct answer is option 2) i.e. B.

Explanation

• The use of preposition 'for' with  the verb 'sympathize' is incorrect. The standard preposition with 'sympathize' is 'with'.

• Sympathize with someone means 'to share someone else's sorrow or anger about someone or something; to comfort someone who is sad or angry.'

• 'Sympathy for' means 'feelings of pity and sorrow for someone else's misfortune.'

• For e.g.  'They had great sympathy for the flood victims'.

The correct answer is option 2) i.e. B.

Explanation:

• Here, we will use the present perfect continuous tense, i.e. 'have been trying'. When we want to show a period of time, by using 'for' or 'since', we always use 'present perfect continuous tense'.
• For e.g. 1) I have been living here for 26 years. & 2) I have been living here since 1990.
• The correct form is: The scientists in America have been trying for long to discover the genes responsible for ageing.

The correct answer is option 3) i.e. carried away.

Explanation

• Carried down means moved something from a higher level to a lower one.
• Carried Aloft means moved up in or into the air.
• Carried away means aroused to a high and often excessive degree of emotion or enthusiasm.
• It is evident from the sentence that a person has heard the speech of another person, which was highly energetic, as a result, he was aroused to a high degree of enthusiasm.

The correct answer is option 1) i.e. rose another two feet.

Explanation:

• Raise means to lift or move something to a higher position or level.
• Rose means something been moved from a lower position to a higher one.
• Rose is second form verb of rise.
• Clearly, the water in the lake was risen due to heavy rains, and not the water in the lake raised something else to another two feet.
  

Mistake Point:

• Aspirants should clearly know the difference between raised and rose. Raised is used to show the level of something else has changed, whereas, rose is used to show, the level of the subject, being talked about, has changed. Refer to above explanation for better understanding.

The correct answer is option 3) i.e. ever.

Explanation  

• Never is a negating word. Negations are words like no, not, and never. Writing without ( a negative word) before never ( a negating word), is redundant and grammatically incorrect expression. We can not write two negative words consecutively.
• Seldom means rarely, not often. This also provides two negative words consecutively. So is the case with hardly, which means very rarely.
• Ever means at any time. This is a positive meaning word, therefore can follow without. 'Without ever seeing the moon and stars' means that one will not see the moon and stars even once.

The correct answer is option 4) i.e. No improvement.

Explanation:

• The given sentence is grammatically correct. Here, those refer to who, which in turn, refers to the graduates. The rest of the expressions are absurd and meaningless to use in the above sentence.
• The sentence means that The Applications of the graduates will be considered.

The correct answer is option 3) i.e. rained.

Explanation

• The expression through + this + (any period of time) means from the beginning to the end of a period of time.
• Here, through this week means right from the beginning to the end of the week. So, the action of raining is a past event. Therefore, we will use simple past for the verb rain and not the continuous form of the verb, i.e. raining, as the action of raining has been already over, when the sentence given above is being said.

• 'Has rained' is incorrect to use here. We use present perfect when an action that began in the past and continues into the present, or whose effects continue into the present. Here, the sentence is being told at the end of the week, so the action or its effects is not present at the time when the sentence is being said. So we can not write 'has rained' here.
• 'Rained' is correct because it is in the simple past. We use simple past tense when an action occurred at some time in the past and it is now complete. At the time, when the sentence is being said, the action of raining is complete, so, write in the simple past, i.e. Rained.

The correct answer is option 1) i.e. notice of.

Explanation

• Notice of something means give attention to something, to observe something.

• The sentence means that the sparrow did not pay attention to or observed the bread.

• Notice from someone means to get any information from someone else

• Notice to someone means to give any information to someone else.

The correct answer is option 2) i.e. tall.

Explanation:

• Tall claim means overstatement or the action of stating something too strongly, exaggeration.
• The above sentence means that as he spoke about his achievements, his exaggeration of his achievements were amusing the listerners.
• For e.g:  The world use to laugh at Wright brothers claiming them to be making tall claims of bringing the dream of man flying to life.

The correct answer is option 4) i.e. No improvement.

Explanation

• Stand for means to be in support of something.
• The given sentence means that we should support the cause which is right.

• Stand at means to reach a particular level.
• Stand on means continue on the same course.
• Stand up means to be or become vertical.

The correct answer is option 2) i.e. telling stories.

Explanation:

• The verb 'enjoy' means ‘get pleasure from something’. It usually has an object. For e.g. We enjoyed the movie so much.
• We use the -ing form of verb after 'enjoy' and we do not use a 'to-infinitive'. For e.g. I never enjoyed cycling.
• So, as per this rule, the given sentence will be written as He enjoys telling stories to children.
  

Mistake point:

• The sentence 'I never enjoyed to cycle' is incorrect as a 'to-infinitive' is used here, i.e. to cycle. The correct sentence will be 'I never enjoyed cycling.'

The correct answer is option 2) i.e. shall have been waiting.

Explanation

• We use the future perfect continuous form when we are looking back to the past from a point in the future and we want to emphasize the length or duration of an activity or event. For e.g. In September the headteacher will have been teaching at the school for 20 years.
• Here, in the given sentence, a point in the future is when the clock strikes six, and a look into the past refers to the time duration of one hour.
• Therefore, 'In a few minutes' time, when the clock strikes six, I shall have been waiting here for an hour.'  is the correct sentence.

The correct answer is option 4) i.e. very loud.

Explanation:

• Dangerous means harmful.
• Terrifying means threatening.
• Mild means not harsh or not dangerous.
• Deafening means So loud as to make it impossible to hear anything else.
• For e.g. The music reached a deafening crescendo.
• In the given options, only 'very loud' carries a similar meaning. So, Option 4 is the correct answer.

The correct answer is 'commendable.'

Key Points

• The given word 'exemplary' means very good; that can be an example to other people. (श्रेष्‍ठ, बहुत अच्‍छा; औरों के लिए आदर्श)
• ​Let's see the meaning of other given options:-
• 'Usual' means happening or used most often. (प्रयोग में आने वाला, हमेशा)
• 'Durable' means likely to last for a long time without breaking or getting weaker. (टिकाऊ, स्‍थायी)
• 'Commendable' means something that people think is good. (सराहनीय, प्रशंसनीय, प्रशंसा योग्‍य)
• 'Some' is used to refer to someone or something that is unknown or unspecified. (किसी अज्ञात या अनिर्दिष्ट व्यक्ति या किसी चीज़ को संदर्भित करने के लिए उपयोग किया जाता है)
  

Hence, the correct answer is option 3.

Additional Information

• The synonyms of the word 'exemplary' are "commendable, excellent, fabulous".
• The antonyms of the word 'exemplary' are "bad, poor, unsatisfactory".
• Example of 'exemplary' in a sentence:
• His citation says he showed outstanding and exemplary courage.

The correct answer is option 4) i.e. Impatient.

Explanation

• Restive means unable to remain still, silent.
• At rest means relaxed, not agitated.
• Idle and Quiet means calm, not troubled.
• Impatient means restlessly eager, showing a tendency to be quickly irritated or provoked.
• Only option 4, i.e. Impatient carries a similar meaning as that of restive, so, option 4 is the correct answer.. Other three are opposite in meaning, so, are antonyms of the word 'restive'.

The correct answer is 'scarcity.'

Key Points

• The given word 'dearth' means a lack of something; not enough of something. (किसी वस्‍तु की कमी; अपर्याप्त)
• ​Let's see the meaning of other given options:-
• 'Scarcity' means the state of being scarce or in short supply; shortage. (विरलता, दुर्लभता, अभाव)
• 'Availability' means the quality of being able to be used or obtained. (उपलब्‍ध होने की स्थिति; सुलभता, प्राप्‍यता)
• 'Plenty' means as much or as many of something as you need. (भरपूर, जितना चाहिए उतना भर)
• 'Absence' means the fact of something or somebody not being there; lack. (किसी वस्‍तु या व्‍यक्ति के किसी स्‍थान पर न होने का तथ्‍य; अनुपस्थिति)
  

Hence, the correct answer is option 1.

Additional Information

• The synonyms of the word 'dearth' are "scarcity, deficit, shortage".
• The antonyms of the word 'dearth' are "excess, overabundance, surfeit".
• Example of 'dearth' in a sentence:
• There's a real dearth of knowledge about how to manage money.

The correct answer is 'went away.'

Key Points

• The given word 'retired' means to leave a room or group of people and go somewhere quiet or private. (एक कमरा या लोगों के समूह को छोड़कर कहीं शांत या निजी स्थान पर जाना)
• For Example - After dinner, our host said, "Shall we retire to the drawing-room?"
• ​Let's see the meaning of other given options:-
• 'Entered' means to become a member of or start working. (सदस्य बनना या काम करना शुरू करना)
• 'Went away' means to leave a place or person. (किसी स्थान या व्यक्ति को छोड़कर दूर चले जाना)
• 'Ran away' means to get free from a dangerous or confining situation. (खतरनाक या सीमित स्थिति से मुक्त होना)
• 'Mobilized' means make something movable or capable of movement. (कुछ चलने योग्य बनाना)
  

Hence, the correct answer is option 2.

Mistake Points

• One must be clear in making out the difference between ran away and went away. Read the above explanation for a better understanding.

Additional Information

• The synonyms of the word 'retired' are "went away, released, separated".
• The antonyms of the word 'retired' are "kept, engaged, retained".
• Example of 'retired​​' in a sentence:
• He took a book from the shelf and retired to his room.

The correct answer is 'strategic.'

Key Points

• The given word 'tactical' means connected with the particular method you use to achieve something. (कुछ प्राप्‍त करने के लिए अपनाई गई युक्ति से संबंधित)
• ​Let's see the meaning of other given options:-
• 'Sensitive' means quick to detect or respond to slight changes, signals, or influences. (ज़रा से परिवर्तन को भी माप लेने वाला)
• 'Strategic' means helping you to achieve a plan. (लक्ष्‍य की प्राप्ति में सहायक युक्तिपूर्ण)
• 'Immediate' means happening or done without delay. (तुरंत होने या किया जाने वाला)
• 'Expert' means having or involving a great deal of knowledge or skill in a particular area. (कुशल, प्रवीण, सुविज्ञ)
  

Hence, the correct answer is option 2.

Additional Information

• The synonyms of the word 'tactical' are "strategic, plan, prudent".
• The antonyms of the word 'tactical' are "impractical, unplanned, unfeasible".
• Example of 'tactical' in a sentence:
• He was given tactical command of the operation.

Explanation

• Deviate means different from usual or accepted standards.
• Dispute means an argument.
• Disagree means to express a different opinion.
• Distinguish means recognize or treat as different.
• Differ means dissimilar or disagree.
• Though the meanings Disagree, Distinguish and Differ are similar, the correct answer is differ. This is so because of the use of preposition 'from' in the sentence. 'Disagree' is followed by the preposition 'with', 'distinguish' generally by 'between', whereas 'differ' is followed by the preposition 'from'.
• For e.g. He differed from his contemporaries in ethical matter.
• The given sentence, i.e. question sentence means that A genius always thinks the way other the conventional way of thinking.

• Aspirants must be aware with the use of the prepositions after these words, when put in a sentence. Refer the explanation given above.

The correct answer is option 2) i.e. weakened.

Explanation:

• Debilitated means in a very weakened and infirm state.
• Depressed means in a state of unhappiness.
• Worried means anxious, disturbed.
• Defeated means beaten up in a battle or other contest.
• Weakened means became weaker in power, resolve, or physical strength.
• From the given options, option 2, i.e. 'weakened', carries the same meaning as that of the word 'debilitated'.
• The sentence means that the person was greatly weakened by the attack of influenza.
  

Important point:

• Aspirants should be careful in using the words weakened and defeated. Defeated means beaten in a conflict, whereas, debilitated, means to become weak. It is not necessary that the weak have been defeated.

The correct answer is option 4) i.e. praiseworthy.

Key Points:- 

• The sentence expresses the meaning that the efforts of the person in relation to helping the poor are deserving admiration. (वाक्य इस अर्थ को व्यक्त करता है कि गरीबों की मदद करने के संबंध में व्यक्ति के प्रयास प्रशंसा के पात्र हैं।)
• Laudable means deserving praise and commendation. (प्रशंसा के योग्य )
• Welcome means an instance or manner of greeting someone. (किसी का अभिवादन करने का उदाहरण या ढंग)
• Sincere means genuine, honest. (सच्चा, ईमानदार)
• Good means something of high standards. (उच्च मानकों का कुछ)
• Praiseworthy means deserving approval and admiration.
• From the given options, only option 4 carries a similar meaning as that of the word laudable.
• Therefore, option 4 is the correct answer.

The correct answer is option 1) i.e. rebuke.

Explanation:

• Reproach means the expression of disapproval or disappointment.
• Sympathy means feelings of pity and sorrow for someone else's misfortune.
• Indifference means a lack of interest.
• Remorse means a deep regret or guilt for a wrong committed.
• Rebuke means to express sharp disapproval or criticism.
• From the given options, only option 1, i.e. rebuke carries a similar meaning as that of the word reproach. The question sentence means that the behavior of the person resulted in his sharp criticism by the sections of his society or surroundings. So, rebuke is the correct answer.
• For e.g. She had rebuked him for drinking too much.

The correct answer is option 1 i.e. Both the Statements are individually true but Statement II is not the correct explanation of Statement I. Petroleum

• Petroleum is referred to as “Black Gold.”
• Crude oil is taken into account to be the “mother of all commodities” because it is employed to manufacture various products like pharmaceuticals, plastics, gasoline, synthetic fabrics, etc.
• Petroleum or oil has also been the world’s leading source of energy since the 1950s.
• When it's drilled from the bottom within the liquid form, it's called petroleum.
• Petroleum is made from the remains of dead plants and animals.
• Certain bacteria helped within the decomposition of this organic matter and caused some chemical changes.
• Matter consisting of largely carbon and hydrogen (Hydrocarbon) was left behind. However, as there's not sufficient oxygen at the rock bottom of the ocean, the matter couldn't decompose completely.
• This burying took many years, and eventually, thanks to heat and pressure, the organic matter decomposed completely and formed oil. Hence statement I is true.
• Petroleum may be a mixture of the many substances like gas, petrol, diesel, kerosene, grease, paraffin, etc.
• The grade of petroleum depends mainly on the relative proportion of the different hydrocarbons, and other factors such as its specific gravity or API and its sulphur content—and its location—for example, its proximity to tidewater and/or refineries. Hence statement 2 is the true and correct explanation of statement 1.
• ​India’s strategic crude oil storages are currently located at Visakhapatnam (Andhra Pradesh), Mangaluru (Karnataka), and Padur (Karnataka).
• The government has also given approval for setting up of two additional facilities at Chandikhol (Odisha) and Padur (Karnataka).

The correct answer is option 1 i.e. Both the Statements are individually true and Statement II is the correct explanation of Statement I.

Red sea

• The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia.
• The connection to the ocean is within the south through the Bab-el Mandeb strait and therefore the Gulf of Aden.
• To the north lie the Sinai Peninsula, the Gulf of Aqaba, and thereafter the Gulf of Suez (leading to the Suez Canal).
• The sea is underlain by the Red Sea Rift which is a small portion of the Great Rift Valley.
• The salinity of the Red Sea is greater than the world average, approximately 4 %. Hence statement 1 is true.
• This is due to several factors:

1. There is a lack of significant rivers or streams draining into the ocean.
2. There is a limited connection with the Indian Ocean, which has lower water salinity.
3. The high rate of evaporation and very little precipitation. Hence statement 2 is the true and correct explanation of statement 1.

The correct answer is option 2 i.e. Both the Statements are individually true but Statement II is not the correct explanation of Statement I.

Volcano

• A volcano is an opening in the earth’s crust through which gases, molten rocks lava, ash, steam etc. are emitted outward in the course of an eruption.
• Such vents or openings occur in those parts of the earth’s crust where the rock strata are relatively weak.
• Volcanic activity is closely connected with crystal disturbances, particularly where there are zone weakness due to deep faulting or mountain folding.
• Major earthquakes usually caused by movement along faults.
• This is because the molten magma float over the asthenosphere that forces its way into the planes of weakness of the crust to escape.
• Hence both the statements are individually true but Statement II is not the correct explanation of Statement I.
• There are three types of volcanoes i.e. active, dormant and extinct.
• When volcanoes frequently errupted or errupted within recent time are said to be active.
• Those shows the signs of possible erruption in the future are said to be dormant.
• Volcanoes that have not errupted at all in historic times but retain the features of volcanoes are termed as extinct.

The correct answer is option 3 i.e. Statement I is true but Statement II is false.

Plantation Farming

• Plantation farming is bush or tree farming. It was introduced by the British in the 19th century.
• It is a single crop farming of rubber, tea, coffee, cocoa, spices, coconut and fruit crops like apples, grapes, oranges, etc.
• It is capital intensive agriculture.
• Plantation agriculture is export-oriented agriculture. Most of the crops grown in plantation agriculture have a life cycle of more than two years.
• Natural rubber, coconuts, oil palm, tea, cocoa, and coffee are all tree crops and take years to mature, but afterwards, they are productive for long periods.
• Plantations are mainly found in countries that have a tropical climate. Plantations exist on every continent possessing a tropical climate. Hence statement I is true.
• Clay soil that is commonly found in tropical regions has very good drainage and high humid content.
• The humid tropical soil has less fertile because the decomposition rate of organic matter is very slow due to all-weather filled with water and hence less organic matter present in the soil. Hence statement II is false.

The correct answer is option 1 i.e. Both the Statements are individually true and Statement II is the correct explanation of Statement I.

Population density and population distribution

• There are several factors that affect the population distribution in India like Geographical Factors, Social Factors, Cultural Factors and Economic Factors

​Geographical Factors

• It includes topography because people prefer living on plains rather than plateaus and mountains since these areas are suitable for agriculture, manufacturing and also service activities.
• The Ganga Plains are one of the most densely populated areas of the world whereas mountains like the Alps, Andes and the Himalayas are sparsely populated.
• The other factor is climate, people generally stay away from an extreme climate like the Sahara desert and the polar regions.
• Fertile soils like Brahmaputra and Ganga plain are highly populated.
• People prefer to live in those places where freshwater is easily available. So, the river valleys are densely populated and the deserts have less population.
• Places with deposits of the mineral are naturally more populated.

Social Factors

• Areas with better housing, transport, health facilities and education are more populated. Example: Pune in India

Cultural Factors

• Places with cultural, religious or historical importance attract people. Example: Varanasi in India

Economic Factors

• It is also a reason behind population distribution because Industrial areas offer employment opportunities. A large number of people make their way into these areas. Examples: Mumbai in India

An area like agricultural productivity and history of settlement act like Growth centre and Growth pole is densely populated.

CONCEPT:

Density (ρ):

• The mass per unit volume is called as the density of the material.
• Density is a scalar quantity.
• The density of water is 1000 kg/m³
• Mathematically density can be written as,

$Density;\left( \rho \right) = \frac{{Mass;\left( M \right)}}{{Volume;\left( V \right)}};;;;; \ldots \left( 1 \right)$

⇒ M = ρ V

• The weight,

W = Mg       ...(2)

Where M = Mass, V = The volume of the container

EXPLANATION:

Given:  ρm = 13600 kg/m3, ρW = 1000 kg/m3 (Known data)

• Here we have a container in which we first take water and then we take mercury in the same container.
• Volume for both water and mercury will be the same because the container is the same.
• When the container is filled with water then using equations 1 and 2,

⇒ Mass of water (M_w) = ρ_w × V = 1000V kg

⇒ Weight of water (X) = M_W g = 1000Vg       -----(3)

• When the container is filled with mercury then using equations 1 and 2,

⇒ Mass of mercury (M_m ) = ρ × V = 13600V Kg

⇒ Weight of mercury (Y) = M_m g = 13600Vg      -----(4)

• Divide the equation (2) by (1) we get,

$⇒ \frac{Y}{X} = \frac{{13600;Vg}}{{1000;Vg}} = 13.6$

⇒ Y = 13.6 X

Sp the correct answer is option 3.

CONCEPT:

Density:

• The mass per unit volume is called as density of material.
• Density is a scalar quantity.

EXPLANATION:

• When the water molecules are present in ice form then it has lot of empty space within molecules.

• When water melts then after converting into water the molecules gets closer to each other and they will be most closed to each other at 4°C.

• Hence the density of water at 4°C is maximum which is 1000 kg/m³. So option 3 is correct.

• When immiscible liquids of different densities are poured in a container, the liquid of the highest density will be at the bottom while that of the lowest density at the top and interfaces will be plane.

The correct answer is option 1, i.e Red Phosphorus.

Allotropes of Phosphorus

• There are different allotropic sorts of Phosphorus in nature.
• The important allotropic sorts of phosphorus are white phosphorus, black phosphorus and red phosphorous.

Red Phosphorus

• Has iron-grey lustre.
• Odourless.
• Nonpoisonous.
• It does not dissolve in water and carbon disulphide.
• Does not glow in the dark.
• Chemically, white phosphorus is more reactive than red phosphorus.
• It is polymeric and consists of chains of P4 tetrahedra linked together.
• It is used in the manufacturing of safety matches.

White Phosphorus

• It appears like white waxy solid or translucent.
• Poisonous in nature.
• Less stable and more reactive.
• Does not dissolve in water.
• When mixed with carbon disulphide it dissolves and evaporates to sunlight to form Scarlet phosphorus.
• Glows in the dark.

Black Phosphorus

• α-black and β-black are two sorts of black phosphorus.
• When red phosphorus is heated in a sealed tube at 803K, an α-black form is formed.
• It can be sublimed in the air and has either rhombohedral crystals or opaque monoclinic.
• It does not oxidise in the air.
• When the white phosphorus is heated under high pressure at 473 K, β-Black is formed, It does not burn in the air up to 673K.

The correct answer is option 3 i.e. Freezing of water.

Key Points

Chemical changes

• If the chemical composition of a product is changing then it is a chemical change.
• The changes are irreversible changes.
• And the final product is different from the initial one.
• Example of Chemical changes is the burning of a candle, the ripening of fruit, curdling of the milk, and the digestion of food, etc.

Physical changes

• if the chemical composition is remaining the same but only the state changes, then it is a physical change.
• The changes are reversible change.
• The states changes but the final products are the same as the initial one.
• Example of Chemical changes is Freezing of water and Evaporation of water etc. Hence option 3 is correct.

The correct answer is option 4, i.e 1, 2 and 4 only.

Air pollution

• Air pollution refers to any physical, chemical or biological change in the air.
• It is the contamination of air by harmful gases, dust and smoke which affects plants, animals, and humans drastically.
• This can be in the form of excessive gases like carbon dioxide and other vapours that cannot be effectively removed through natural gaseous cycles.
• There are two types of Pollutants that cause air pollution i.e Primary pollutants and Secondary pollutants.
• Primary pollutants are the pollutants that directly cause air pollution like Lead, Fly Ash, Metallic Oxides and Nano-particles etc.
• Secondary pollutants formed by the reaction of primary pollutants like Carbon monoxide (CO), Carbon dioxide (CO₂), Chlorofluorocarbons (CFCs), Ozone (O₃), Nitrogen oxide (NO_x), Volatile organic compounds (VOCs), Benzene, Biological pollutants, Asbestos and Radon etc.
• Carbon monoxide (CO), Nitrogen oxide (NOx), Benzene, Ozone (O3) and Chlorofluorocarbons (CFCs), are pollutants that are not tolerated by human beings even at very low levels. Hence option 4 is correct
• There are some air pollutant and their health impact listed below.

The correct answer is option 1, i.e 4 – 3 – 1 – 2.

Bhubaneshwar

• Bhubaneshwar is one of the largest capital of Indian state Odisha, which is the easternmost state of Peninsular India.
• Bhubaneswar is also popularly known as the "Temple City of India".
• Being the seat of Tribhubaneswar or 'Lord Lingaraj', Bhubaneswar is an important Hindu pilgrimage centre.

Patna

• Patna is an ancient city that sprawls along the south bank of the Ganges River in Bihar, northeast India.
• It the capital of Bihar, the northeastern state of India.
• It is famous for the Buddhist, Hindu and Jain pilgrimage centres of Vaishali, Rajgir, Nalanda, Bodh Gaya and Pawapuri.
• Patna City is also a sacred city for Sikhs as the tenth Sikh Guru, Guru Gobind Singh was born here.
• Bhubaneshwar is in the east of this city.

Rishikesh

• Rishikesh is a city in India’s northern state of Uttarakhand, in the Himalayan foothills beside the Ganges River.
• Rishikesh is primarily famous for its spiritual importance.
• There are a number of Yoga Ashramas for practising meditation.
• Rishikesh is the beginning of the famous Char Dham Yatra.
• It is in the Northeast to Delhi which is the capital of India.

Delhi

• It is the National Capital Territory of Delhi (NCT), a city and a union territory of India containing New Delhi, the capital of India.
• It is famous for its tourist attractions, food, and it's marketplaces.

CONCEPT:

Newton's law of Gravitation:

• Newton's law of gravitation states that everybody in this universe attracts every other body with a force, which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
• The direction of the force is along the line joining the particles.
• The magnitude of the gravitational force F is,

$F = G\frac{{{M_1}{M_2}}}{{{R^2}}};;;;; \ldots \left( 1 \right)$

Where G = universal gravitational constant, M1 = mass of 1st body, M2 = mass of 2nd body, and R = distance between the two bodies.

EXPLANATION:

Given: The two masses are equal.

⇒ m₁ = m₂ = m

• The magnitude of the gravitational force F using equation 1 in 1^st case is

$⇒ F = {\rm{;}}G;\frac{{{m_1}{m_2}}}{{{r^2}}} =;\frac{{G;{m^2}}}{{{r^2}}}$

• Now masses are doubled and distance is the same

⇒ m₁ = m₂ = 2m

• The magnitude of the gravitational force F using equation 1 in 2nd case is

$\Rightarrow F = ;G;\frac{{2m \times 2m;}}{{{r^2}}}$

$\Rightarrow F' = ;4 \times \frac{{G;{m^2}}}{{{r^2}}} = {\rm{;}}4{\rm{F;}}$

So, the correct answer is option 3

CONCEPT:

• The energy of anybody due to its position is called as potential energy of that body.
• The energy of anybody due to the motion of that body is called kinetic energy.
• The sum of potential energy and kinetic energy is equal to the total energy of the body.
• According to the energy conservation principle, the total energy of the body always remains constant.
• Potential energy,

PE = m g h

Where m is the mass of the body, g is the acceleration due to gravity and h is height of the body

• Kinetic energy,

 $KE =\frac{1}{2}m{V^2}$

Where m is the mass of the body and V is the velocity of the body

EXPLANATION:

Given: The initial height of the body (H) = 20 m, PE_i = mgH = 20 mg

• When body fall by 5 m then-new height (h) = 20-5 = 15
• Final potential energy (PE_f)= m g h = 15 mg
• Loss in potential energy,

⇒ ΔPE = Initial Potential energy (PEi) - Final potential energy (PEf) 

⇒ ΔPE = 20 mg -15 mg = 5 mg

$\Rightarrow \frac{{Loss;in;potential;energy}}{{Initial;potential;energy;}} = ;\frac{{5mg}}{{20mg}} = \frac{1}{4}$

• Potential energy will lose by one-fourth. Hence option 2 is correct.
• As the total energy will remain constant always, options 1 and 4 are wrong.

The correct answer is option 4.

Saponification

• Soap is sodium or potassium salt of fatty acid produced by saponification reaction using sodium or potassium hydroxide with vegetable or animal oil or fatty acid.
• The fatty acids like stearic, palmitic, myristic, lauric and oleic acids, contribute to lathering and washing properties of the soaps. Hence option 4 is correct.
• Sodium salts of fatty acids are known as hard soaps and potassium salts of fatty acids are known as soft soaps.
• Soap is prepared by heating vegetable oil or animal fat containing Glyceryl stearate with concentrated sodium hydroxide solution.
• Hydrolysis of fat takes place and a mixture of sodium salts of fatty acids and glycerol is formed.
• The salts of fatty acids thus formed are used as soap.

CONCEPT:

Mass of a substance:

• Mass is one of the fundamental quantities in Physics and the most basic property of matter.

EXPLANATION:

• The mass of a particular amount of substance depends on the amount of matter present in it. Hence statement 1 is correct.
• The SI unit of mass is the kilogram (kg).
• The mass of a body does not change at any time and it does not vary from place to place. Hence statement 2 is correct.
• Mass can never be zero.
• Mass is a scalar quantity, It has magnitude but not direction.

∵ W = mg

Where W =The weight of the body, m  = The mass of the body, and g = The gravitational force on the body. 

• So, the mass does not change according to the gravitational force but it is the weight that changes with gravitational force.
• Hence, statement 3 is NOT correct.

The correct answer is option 2

The correct answer is option 4.

This is the list of few adulterants added to the food products along with their harmful effects.

Mercury contamination occurs through seafood.

The correct answer is option 2 i.e. Jhelum Valley.

Karewas

• The Jhelum valley is the part of Kashmir valley which is an oval-shaped basin, 140 km long and 40 km wide.
• It is an intermountain valley fill, comprising of unconsolidated gravel and dirt.
• A succession of plateaus or plateau-like terraces is present above the plains of Jhelum and its tributaries, called ‘Karewas’ or ‘Vudr’ within the local language.
• Despite continuous erosion for many years, quite half the valley remains occupied by the Karewa.
• Karewas are lacustrine deposits that mean deposits in the lake, in the Valley of Kashmir.
• These are the flat-topped mounds that border the Kashmir Valley on all sides.
• Karewas were formed during the Pleistocene Period when the entire Valley of Kashmir was underwater.
• Thus they are characterized with fossils of mammals and at places by peat.

The correct answer is option 2 i.e Deccan Plateau.

Meghalaya Plateau

• The Deccan Plateau of peninsular India extends further east beyond the Rajmahal hills to Meghalaya or the Shillong plateau. Hence option 2 is correct.
• Garo-Rajmahal Gap separates this plateau from the most block.
• This gap was formed by down-faulting. It was later filled by sediments deposited by the Ganga and Brahmaputra.
• The plateau is made by Archaean quartzites, shales and schists.
• The plateau slopes right down to Brahmaputra valley within the north and therefore the Surma and Meghna valleys within the south.
• Its western boundary coincides with the Bangladesh border.
• The western parts of the plateau are known as the Garo Hills, central parts of the plateau are known as the Khasi-Jaintia and the eastern parts of the plateau are known as the Mikir Hills.
• Shillong is the highest point of the plateau.

CONCEPT:

Momentum:

• The product of mass and velocity is called as the momentum of any body.
• It is denoted by P.
• Momentum can be written mathematically as
• P = m × V      ...(1)

Where m is mass and V is the velocity of the body

EXPLANATION:

Given: Mass of B (MB) = 2MA (Mass of A) and V_A = V_B

• Using equation 1, the momentum of body A,

⇒ P_A = M_A × V_A      --------- (2)

• The momentum of body B,

⇒ P_B = M_B × V_B = (2M_A ) × V_A      --------- (3)

Divide equations 2 and 3, we get

$\Rightarrow \frac{{{P_A}}}{{{P_B}}} = \frac{{{M_A}{V_B}}}{{2{M_B}{V_B}}} = \frac{1}{2}$

• ∴ The momentum of body B is twice that of body A.

So, the correct answer is option 1.

The correct answer is option 2.

Solar eclipse

• A Solar eclipse is a phenomenon that occurs when the moon comes in the way of the sun’s light. Hence option 2 is correct.
• The moon's shadow casts itself on Earth, blocking out the sun's light.
• The moon's shadow has two parts: a central region called the umbra and an outer region called the penumbra.
• From the umbra, we see a total eclipse while from the penumbra only a partial eclipse is visible.
• Depending on the distance of the moon from the earth during the event three types of solar eclipses could be observed.

1. Total Solar Eclipse- The entire central portion of the sun is blocked out by the moon.
2. Partial Solar Eclipse- Only part of the sun's surface is blocked out.
3. Annular Solar Eclipse- The sun is covered in such a way that only a small ring-like sliver of light is seen from the sun's disc. This ring is known as the ring of fire. An annular eclipse happens when the moon is farthest from Earth.

CONCEPT:

• Acceleration (a): The rate of change of velocity is called the acceleration of the body.

$a = \frac{{Change;in;velocity;\left( {{\rm{\Delta }}V} \right)}}{{Time;taken;\left( t \right)}}$

EXPLANATION:

• As we know that the SI unit of velocity = meter/sec
• **The SI unit of time = **sec
• ∴ SI unit of acceleration is,

$\Rightarrow a = \frac{{meter/sec}}{{sec}} = \frac{{meter}}{{se{c^2}}} = m/{s^2}$

• The correct answer is m/s2.

​

• The CGS unit of acceleration is cm/s².

The correct answer is option 2 i.e.6.

Mass number

• The mass number can be calculated as the total number of protons and the number of neutrons in an atom.
• mass number = protons + neutrons
• As per given in the above question we have - Mass number=12, proton=6 and neutrons=?
• 12 = 6 + Number of neutrons
• Number of neutrons = 12 - 6
• Number of neutrons = 6

The correct answer is option 3.

Explanation:

Reduction reaction

• Reduction means losing oxygen in a chemical reaction.
• In terms of electrons, the reduction occurs when an atom, molecule, or ion gaining one or more electrons in a chemical reaction.
• When oxidation occurs, the oxidation state of the chemical species decreases.
• An example of the reduction reaction is
• $2HgO\left( s \right)\overset{heat}{\mathop{\to }},2Hg\left( l \right)+{{O}_{2}}\left( g \right)$, where the oxidation number of Hg is decreasing from +2 in LHS to 0 in RHS. Hence option 3 is correct.

Important Points

Oxidation reaction

• Oxidation means gaining oxygen in a chemical reaction.
• In terms of electrons, oxidation occurs when an atom, molecule, or ion loses one or more electrons in a chemical reaction.
• When oxidation occurs, the oxidation state of the chemical species increases.
• An example of the oxidation reaction is 
• 2Mg (s) + O2(g) → 2MgO(s), where oxidation number of Mg is increases from 0 in LHS to +2 in RHS.
• S(s) + O2(g) → SO2(g), where oxidation number of S is increases from 0 in LHS to +4 in RHS.
• Mg(s) + S(s) → MgS(s) where oxidation number of Mg is increases from 0 in LHS to +2 in RHS.​

The correct answer is option 3

Bisphenol A (BPA)

• Bisphenol A (BPA) that is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics and epoxy resins.
• BPA applications including use in some food and drink packaging, e.g., water and infant bottles, coffee mugs, compact discs, impact-resistant safety equipment, and medical devices.
• Steel utensils and Aluminium utensils donot release BPA.
• BPA that seeps into food and drink is taken under consideration safe in low doses, but prolonged exposure is suspected of affecting the health of kids and contributing to high blood pressure.
• The primary source of exposure to BPA for many people is through the diet.
• BPA is an endocrine-disrupting chemical.
• The toxic chemical is known to mimic a hormone that activates the progression of cancer and interferes with the development of the reproductive system.
• Epidemiological studies of children indicate correlations between BPA exposure and heart diseases, liver toxicity, and metabolic syndrome.

The correct answer is option 2 i.e. Krishna.

Key Points 

Nagarjun Sagar project

• Nagarjuna Sagar Dam is a reservoir across the river Krishna in Nagarjuna Sagar Nalgonda district of Andhra Pradesh.
• Nagarjuna Sagar Reservoir is the world's largest man-made Lake with a concrete wall that measures 6 feet thick.
• It provides irrigation water to the Nalgonda, Prakasam, Khammam and Guntur district.

There are list of some major dam of India are given below:

The correct answer is option 3, i.e Both 1 and 2.

Rajmahal Hills

• Rajmahal hills lies to the east in the state of Jharkhand in India.
• It is the part of peninsular plateau is the oldest and largest physiographic unit of India.
• Rajmahal highlands consist of multiple layers of lava flow deposits which is predominantly tholeiitic basalt, quartz tholeiite, olivine tholeiite and alkali basalt. Hence the statement 1 is correct.
• The River Ganga meanders around the hills changing the direction of flow from eastwards to southwards.
• Volcanic activity in the Jurassic era caused the formation of these hills.
• The upper regions of the Rajmahal Hills are inhabited by the Sauria Paharia tribe while the valleys are dominated by the Santhal tribe who cultivate the land.

 Bundelkhand

• Bundelkhand is the part of peninsular Plateau which is one of the oldest landforms of earth.
• It is a highly stable block composed mostly of the Archaean gneisses and schists. Hence the statement 2 is correct.
• It extended from Yamuna river to the north, Madhya Bharat Pathar to the west, Vindhyan Scarplands to the east and south-east and Malwa Plateau to the south.
• It is the old dissected or divided by a number of deep valleys, upland of the ‘Bundelkhand gneiss’ comprising of granite and gneiss rock
• River Betwa, Dhasan and Ken flow through the plateau.

CONCEPT:

• The mirror which has a spherical reflection surface is called as spherical mirror.
• The spherical mirror whose reflecting surface is away from the center of curvature is called as convex mirror.
• Convex mirror always from a virtual image of any object.
• The mirror whose reflecting surface is inward is called as concave mirror.
• The concave mirror can form both real as well as virtual image of any object.

EXPLANATION:

Given: Focal length (f)  of concave mirror = 16 cm

• Since the object is shifted towards focus by 8 cm so object is between focus and center of curvature of the mirror.

• When the object is between focus and Centre of curvature the image formed by the concave mirror is real and magnified. Hence option 1 is correct.
  

• The real image is always inverted.

• Virtual image is always erect.

Concept-

• The transparent curved surface which is used to refract the light and make an image of any object placed in front of it is called a lens.
• The lens whose refracting surface is upside is called a convex lens.
• The convex lens is also called a converging lens.
• The lens having refracting surface inward is called a concave lens.
• The concave lens is also called a diverging lens.

Explanation-

• Here we have a pencil as an object for the lens.
• Since the focal length is 15 cm and the object is at 10 cm from the lens. So the object is placed between the lens and the focus.

Here F is the focus of the lens and P is the optical center of the lens

• When an object is kept between lens and focus of a convex lens then the image form on the same side of the lens.
• The image formed is virtual and magnified.
• The virtual image is erect. Hence option 4 is correct.

The correct answer is option 4, i.e Biomass energy.

Conventional energy source

• Conventional energy sources are the natural energy resources which are present in a limited quantity and are being used for a long time.
• If once they are depleted, called non-renewable sources, being used up more quickly than it can replace itself.
• They are formed from decaying matter over hundreds of millions of years.
• These resources have been depleted to a great extent due to their continuous exploitation.
• Examples of conventional sources of energy include coal, petroleum, biomass, natural gas and electricity. Hence option 4 is correct.

Non-Conventional energy source

• Non-conventional sources of energy are the energy sources which are renewable by natural processes.
• These cannot be exhausted easily, can be generated constantly so can be used again and again.
• These sources do not pollute the environment and do not require heavy expenditure.
• They are called renewable resources as they can be replaced through natural processes at a rate equal to or greater than the rate at which they are consumed.
• Example of Non-Conventional energy source includes solar energy, wind energy, tidal energy, biogas and geothermal energy etc. Hence option 1, 2 and 3 are incorrect.

The correct answer is option 2 i.e.N2O₅

Key Points</sub>

Acid anhydride

• Anhydride means ‘without water’ It can be defined as the chemical compound formed by eliminating water from another compound.
• Anhydrides react with water to produces either base or an acid.
• Acid anhydrides are the molecules that are capable of forming acidic solutions in water.
• Dinitrogen pentoxide (N₂O₅) is the anhydride of nitric acid.
• It means Hydration of Dinitrogen pentoxide (N2O5) gives Nitric acid.
• N2O₅ + H₂O → 2HNO₃

The correct answer is option 1 i.e. Sodium bicarbonate.

• Some common name of the chemical compound, their chemical name, and chemical formula are as follows:

Important Points