Explore topic-wise InterviewSolutions in Current Affairs.

One day the young lad was lying on his back dreaming for a cup of good coffee.

Sieving is a method by which fine particles are separated from bigger particles by using a sieve. Sieving is used when components of a mixture have different sizes. 

It is used in flour mill, construction sites and our homes.

Water is an essential form of life. It is a basic necessity for all terrestrial forms of life. Water is useful in agriculture, industries, cooking and various domestic activities. Most of us depend on rainfall for water.

The rainfall pattern in India differs in different geographical regions. Rains in India are largely due to the monsoons. Tropical regions receive more rainfall as compared to desert regions.

Despite nature’s monsoon bounty, failure to sustain water availability underground has resulted largely from the loss of vegetation cover, diversion for high water demanding crops, and pollution from industrial effluents and urban wastes. Irrigation methods like dams, tanks and canals have been used in various parts of India since ancient times. These were generally local interventions managed by local people and assured that the basic minimum requirements for both agriculture and daily needs were met throughout the year.

Sustainable development is not only about the resources we use but also ensures that they are equally distributed. Stakeholders together help in sustainable management. The Chipko  Andolan ('Hug the Trees Movement') originated in the 1970's, in a village called Reni in  Garhwal high up in the Himalayas. It was to save trees from being cut down. The Chipko movement quickly spread across communities and media and forced the government, to whom the forest belongs, to rethink their priorities in the use of forest products. Experience has taught people that the destruction of forests affected not just the availability of forest products, but also the quality of soil and the sources of water. Participation of the local people can indeed lead to the efficient management of forests.  

Government should control the industries in using raw materials. Government should also control illegal activities. Industries should play an important role in the management of natural resources.

It happens because of sublimation

These are the atoms of the same element having the same atomic number but different mass number.

e.g., H¹ ,₁H² ,₁H³

The numbers from 1 to 70 that have their squares ending in digit 1 are : 

1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69 i.e., 14 in numbers.

\(\therefore\) Required percentage = \(\frac{14}{70}\) x 100 = 20%

Let the maximum marks be x. Then,

Pass mark for the 1st student = \(\frac{20}{100}\) x x + 5

Pass mark for the 2nd student = \(\frac{30}{100}\) x x - 20

Since pass marks are same for both the students,\(\frac{20X}{100}\) + 5 = \(\frac{30X}{100}\) - 20

\(\Rightarrow\) \(\frac{10X}{100}\) = 25  \(\Rightarrow\) x = 250

\(\therefore\) Pass mark = \(\frac{20}{100}\) x 250 + 5 = 55

Pass percentage = \(\frac{55}{250}\) x 100 = 22%

(d) 25%

Let the maximum marks be M. Then, Pass marks = 20% of M + 30 = 32% of M – 42

\(\Rightarrow\) 12% of M = 72  \(\Rightarrow\) M = \(\frac{72\times100}{12}\) = 600

\(\therefore\) Pass marks = 20% of 600 + 30 = 150

\(\Rightarrow\) Percentage of pass marks = \(\frac{150}{600}\) x 100%

= 25%

(b) Rs 35

Let the cost of one apple and one orange be Rs x 

and Rs y respectively. 

Then, according to the given question,

8x + 5y = 92   ........(i)

5x + 8y = 77  .........(ii)

Multiplying eqn (i) by 5 and eqn (ii) by 8, we get

40x + 25y = 460 ….....(iii)

40x + 64y = 616 …....(iv)

Subtracting eqn (iii) from eqn (iv),

39y = 156

\(\Rightarrow\) y = \(\frac{156}{39}\) = 4

From (i) putting the value of y, we get

8x + 20 = 92

\(\Rightarrow\) 8x = 72 \(\Rightarrow\)x = 9

\(\therefore\) Cost of 2 oranges and 3 apples

= 2 × Rs 4 + 3 × Rs 9 = Rs 8 + Rs 27 = Rs 35.

(d) 13

Let the number of pencils and pen with X be x and y respectively,

Given,  x + y = 40 ........(i)

Also (x + 5) = 4(y – 5)

\(\Rightarrow\)x + 5 = 4y – 20

\(\Rightarrow\) x – 4y = –25  ......(ii)

Subtracting eqn (ii) from eqn (i), we get

5y = 65

\(\Rightarrow\) y = 13.

(d) Rs 12500

Let the father’s salary be Rs x. Then, 

Part of salary given to the two sons as pocket money =\(\frac{X}{100}\)

Share of the elder son = \(\frac{80}{100}\) x \(\frac{X}{100}\) = \(\frac{4X}{500}\)

Expenditure of the elder son =  \(\frac{80}{100}\) x \(\frac{4X}{500}\)

= \(\frac{16X}{2500}\)

\(\therefore\) Savings of the elder son = \(\frac{4X}{500}\)- \(\frac{16X}{2500}\) = \(\frac{4X}{2500}\)

Given, \(\frac{4X}{2500}\) = Rs 20

\(\Rightarrow\) x = Rs \(\frac{20\times 2500}{4}\) =Rs 12500.

(b) 20%

Let B’s salary be Rs 100. Then, 

A’s salary = Rs 125

\(\therefore\) Required % = \(\frac{25}{125}\) x 100% = 20%

(c) 58.8

A = \(\frac{120}{100}\)B, B = \(\frac{120}{100}\)C, C = \(\frac{85}{100}\)D

\(\Rightarrow\) B = \(\frac{5}{6}\)A, C = \(\frac{5}{6}\)B, D= \(\frac{20}{17}\)D

\(\therefore\) B = \(\frac{5}{6}\)x 576 = 480;  C = \(\frac{5}{6}\) x 480 = 400;

D = \(\frac{20}{17}\) x 400 = \(\frac{8000}{17}\)

So, required percentage = \(\big(\frac{8000}{17}\times\frac{1}{800}\times100\big)\)%

= 58.82%

(d) Rs 9650

Let the annual income of the person be Rs x,

Then, 20% of (x – 1,00,000) = 3160

\(\Rightarrow\)x - 1,00,000 = \(\frac{3160\times100}{20}\) = 15800

\(\Rightarrow\) x = 115800

\(\therefore\) Monthly income = Rs \(\frac{115800}{12}\) = Rs 9650

Number of benches required to seat 160 students= 40 

On one bench, the number of students that can be seated = \(\frac {160}{40}\) = 4.40

∴ For 240 students the number of benches required = \(\frac {240}{4}\) = 60

(a) \(2\frac{1}{2}\)% decrease

Let the price of the article be Rs x and daily sale be y units.

Then, daily sale receipts = Rs xy

Reduced price of the article =Rs \(\frac{3}{4}\)x

Increased daily sale = Rs \(\frac{13}{10}\)y

\(\therefore\) Daily sale receipts = Rs \(\frac{3}{4}\)x x \(\frac{13}{10}\)y = Rs \(\frac{39}{40}\)xy

\(\therefore\) % reduction = \(\frac{Xy-\frac{39}{40}Xy}{Xy}\)x 100%

= \(\frac{100}{40}\)% = 2.5%

(c) 48.8%

New value of x = \(\frac{80}{100}\)x = 0.8x

New value of y² = \(\frac{80}{100}\)y x \(\frac{80}{100}\)y = 0.64y²

^{\(\therefore\)} New value of expression = 0.8x x 0.64y²

= 0.512 xy²

^{\(\therefore\)} % reduction in the value = \(\frac{Xy-0.512Xy^2}{Xy^2}\)x 100%

= (0.488 × 100)% = 48.8%

(a) 10% decrease

Let the original price of the book be Rs 100. 

Decreased price of the book = Rs 75 

Increased price of the book after 20% increase

= \(\frac{120}{100}\) x Rs 75 = Rs 90

\(\therefore\) Net change in price = Rs 10 decrease

\(\therefore\) % change = \(\frac{10}{100}\) x 100 = 10% decrease.

(d) \(\frac{10000}{10000-r^2}\)

Let the original price of the article be Rs x. Then,

Increased price of the article =\(\big(\frac{100+r}{100}\big)\) x x

Decreased price of the article after r % decrease

= \(\big(\frac{100-r}{100}\big)\)\(\big(\frac{100-r}{100}\big)\)x x 

Given\(\frac{10000-r^2}{10000}\) x x = 1

\(\Rightarrow\) x = \(\frac{10000}{10000-r^2}\)

(a) 12%

Quantity of alcohol in 3 litres of solution

= \(\frac{20}{100}\) x 3 = \(\frac{3}{5}\)L

Strength of alcohol in new solution = \(\frac{315}{5}\)x 100 = 12%

Elicit free responses

Not to paint the picture.

Paint the picture as the courtiers had demanded. 

Paint the picture as the Archduke had instructed.

Tyl: Ey, Luke How are you?

Friend: Hi Tyl. I am doing good. I heard that you are the new painter at the court of the Archduke. 

Tyl Yes, but I am in great trouble now. Friend: What happened?

Tyl: It is a long story. The Archduke wants me to paint his portrait so as to leave his memory to his descendants. 

Friend: Oh Great.

Tyl: The Archduke demanded me to paint all the courtiers as such but the courtier demanded that I should make them more attractive than they actually were. If I paint the picture as directed by the Archduke, I will be killed by the courtiers. If my picture satisfies the whims of the courtiers I will be killed by the Archduke. Friend: Oh my God! So sad. What will you do again? 

Tyl: I have thought of an idea. I am going to tell them that only those who have noble blood in their veins can see the painting. All the rest would only see a blank wall. This is the only way I found to escape from them. Yesterday I had asked the Archduke more time to finish the painting and he gave me two more days. 

Friend: That’s a good idea hut be careful. If anyone finds out you will be in more trouble. 

Tyl: Yes I must be alert.

Tyl wanted to become the painter at court of the Archduke. He had a good sense of humor and valued his own freedom and creativity. He had a donkey called Jeff along with him. He showed the painting of Our Lady, The Virgin’ to the Archduke. The Archduke was flattered by the painting and gave Tyl the position of the court painter. One day the Archduke wanted his portrait to be drawn by Tyl. Tyl being clever convinced the Archduke that he wouldn’t feel happy about the painting without the others in it. The Archduke accepted his idea and commanded him to draw a portrait which included her highness, the noble generals and the captains.

Tyl was granted hundred gold pieces in advance. The next day as per Tyl’s wish all the courtiers who were to painted came to see him one by one. The Commander in chief of the army was a pleasant-looking fellow. But he wanted himself to be painted handsome and threatened to hang Tyl otherwise. Threats like these followed. But the King commanded that the painting should be very I real and if Tyl missed anything in it, he would be slaughtered like a pig. Tyl understood that he was in danger. So he invented a trick. When everybody came to see 1 the painting he told them that only those who had noble blood in their veins would be able to see the painting. All the rest would only see a blank wall. All started to admire the painting. Suddenly the Duke’s jester came and told that he was a fool and he had no blue blood in his veins but even then he couldn’t see the picture. Hearing this Tyl calmly paced away from the hall and ran for hisdffe on his donkey.

He kept on saying that the picture was nearing completion and he needed some more days to complete.

If he painted the picture as directed by the Archduke, he might be killed by the courtiers. If his picture satisfied the whims of the courtiers, he might be killed by the Archduke.

Dear Citizens of Battenburg,

It is saddening to tell you that a cunning painter from Flanders has cheated our Archduke. His name is Tyl Ulenspigel. He had received a hundred pieces of gold to draw a portrait of the Archduke accompanied by the others who adorned the court. All the required materials were provided for the painter to complete the painting. But he tricked everybody and left the place. The painter named Tyl was seen accompanied with donkey called Jeff. He is thin as a skeleton and wore a cap with three bright feathers on it. Anyone which finds him and brings him to the palace will be rewarded two hundred pieces of gold

Tyl is person who wanders from court to court. He is a man with a good sense of humor. His appearance and mannerisms make us think so.

Correct Answer is: (c) Pal

Forest-based occupations will flourish more in Brazil.

नही , ऐसा कोई ऊर्जा का स्रोत नही है जो प्रदुषण मुक्त हो | सौर सेल हालाँकि प्रदुषण मुक्त है परन्तु उस युक्ति को जुटाने में पर्यावरण क्षति ग्रस्त हो सकता है |

नाभिकीय ऊर्जा से उत्पन्न ऊर्जा को नाभिकीय ऊर्जा कहते है | इस प्रकिया के द्वारा अत्याधिक मात्रा में ऊर्जा मुक्त होती है | इस ऊर्जा का उपयोग भाप बनाकर विद्युत् उत्पन्न करने में किया जाता है |

जब भूमिगत जल तप्त स्थलों के संपर्क में आता है तो भाप उत्पन्न होती है | जब यह भाप चट्टानों के बीच फंस जाती हैं तो इसका दाब बढ़ जाता है | उच्च दाब पर यह भाप पाइपों द्वारा निकाल ली जाती है, यह भाप विद्युत जनरेटर की टरबाइन को घुमती है तथा विद्युत उत्पन्न की जाती है | इन तप्त स्थलों से प्राप्त होने वाली ऊर्जा भूतापीय ऊर्जा कहलाती है |

हम जानते है कि जीवाश्मी ईंधन ऊर्जा के अनवीकरणीय स्रोत है | अतः इन्हें बचाने कि आवश्यकता है | पृथ्वी के अंदर कोयले , पेट्रोलियम , प्राकृतिक गैस आदि सीमित मात्रा में मौजूद है | यदि हम इनका प्रयोग इसी प्रकार करते रहे तो ये शीघ्र ही समाप्त हो जाएंगे | अतः हमें ऊर्जा के वैकल्पिक स्रोतों कि ओर ध्यान देना चाहिए |

उतम ईंधन में निम्नलिखित गुण होने चाहिए –

1.  दहन के बाद प्रति एकांक द्रव्यमान से अधिक ऊष्मा मुक्त हो |

2.  यह आसानी से, सस्ती दर पर उपलब्ध हो |

3.  जलने पर अत्याधिक धुआं उत्पन्न न करे |

4.  इसका ज्वलन ताप उपयुक्त हो तथा उष्मीयमान अधिक हो |

महासागरो से प्राप्त होने वाली ऊर्जा कि निम्न सीमाए है – 

1. तरंग ऊर्जा के व्यापारिक उपयोग के लिए तरंगो का अत्यंत प्रबल होना आवश्यक है |

2. ज्वार भाटे के समय जल के स्तर चढ़ने तथा गिराने से ज्वारीय ऊर्जा प्राप्त होती है | बाँध के द्वार पर स्थित टरबाइन ज्वारीय ऊर्जा को विद्युत् ऊर्जा में बदल देते है | परन्तु ये बांध केवल कुछ ही क्षेत्रो में सफल है | 

3. ऊर्जा संयत्रों के निर्माण कि लागत बहुत अधिक होती है तथा ऊर्जा का उत्पादन कम होता है |

सौर कुकर का उपयोग करने के लाभ :

1. यह उपकरण सस्ता है |

2. इसका उपयोग करने से प्रदुषण नही होती है |

3. इनमे कोई गतिमान पुर्जा नही होता है |

सौर कुकर की हानियाँ :

1. ये उपकरण केवल सूर्य के प्रकाश में ही इसका उपयोग किया जाता है |

2. यह भोजन पकाने में sय अधिक लेता है | हां , ऐसे अनेक क्षेत्र है सौर -सेल महगे होते है | जहाँ सौर कुकरों की सीमित उपयोगिता है उदाहरण : अधिक बरसात वाले क्षेत्र , पहाड़ी क्षेत्र आदि |

उर्जा का उतम स्रोत वह है जो –

1.  प्रति एकांक आयतन अथवा प्रति एकांक द्रव्यमान अधिक कार्य करे |

2.  जो आसानी से उपलब्ध हो |

3.  भंडारण तथा परिवहन में आसान हो |

4.  वह सस्ता हो |

5.  जलने पर प्रदुषण न फैलाए |

सौर कूकर के लिए सर्वाधिक उपयुक्त दर्पण अवतल दर्पण है , क्योंकि यह एक अभिसारी दर्पण है | जो सूर्य कि किरणों को एक बिन्दु पर फोकसित करता है ,जिसके कारण शीघ्र ही इसका ताप और बढ़ जाता है |

ऊर्जा के आदर्श स्रोत के गुण :-

1.  सरलता से प्राप्त हो सके |

2.  सस्ता भी होना चहिए |

3.  प्रति एकाक आयतन एव द्रव्यमान अधिक कार्य करे |

हम LPG गैस या विद्द्युतीय उपकरण का उपयोग करेंगे क्योंकि –

1.  इससे अधिक ऊष्मा उत्पन्न होती है |

2.  इसके दहन से धुआं नहीं निकलता है |

3.  यह आसानी से उपलब्ध है तथा इसका उपयोग सुगमतापूर्वक किसी भी समय किया जा सकता है |

4.  यह सस्ता है तथा इसका भंडारण तथा परिवहन आसानी से किया जा सकता है |

5.  इससे वांछित ऊर्जा आवश्यकता अनुसार प्राप्त कर सकते है |

(c)  नाभिकीय ऊर्जा 

(b)  बादलों वाले दिन

कोयला एव पेट्रोलियम के वे स्रोत है जो समापन योग्य है | इनके भण्डार प्रक्रति में सीमित है एव एक ना एक दिन अवश्य समाप्त हो जायेगे | इन ईधन को निर्मित होने में करोड़ो वषों का समय लगा | अत : इन्हें पुन : निर्मित करना असम्भव है |

Motion is of three types :

1. Translatory motion 

2. Rotatory motion 

3. Oscillatory motion.

No, all the motions are not same.

(i) \(\frac{1}{6}\)

If A can do a piece of work in n days, then A can do \(\frac{1}{n}\) of the work in on day

(ii) 18

Number of hours A required do a piece of work : 9 hours 

Let number of hours B required do a piece of work : X hours 

Number of hours required by A and B together to do a piece of work : 6 hours

Work done by A in one hour: \(\frac{1}{9}\)

Work done by B in one hour: \(\frac{1}{x}\)

Work done by A and B together in a hour: \(\frac{1}{6}\)

Work done by A and B together in one hour: \(\frac{1}{9}+\frac{1}{x}=\frac{x\,+\,9}{9x}=\frac{1}{6}\)

∴ \(\frac{x\,+\,9}{9x}=\frac{1}{6}\)

⇒ 6X +54 = 9X

⇒ 3X = 54

⇒ X = \(\frac{54}{3}=18\)

∴ B can do the work 18 hours

(iii) 48

Number of hours A required do a piece of work : 16 hours 

Number of hours B required do a piece of work : 24 hours 

Let number of hours C required to do a piece of work : X hours 

Number of hours required by A, B and C together to do a piece of work : 8 hours

Work done by A in one hour: \(\frac{1}{16}\)

Work done by B in one hour: \(\frac{1}{24}\)

Work done by C in one hour: \(\frac{1}{x}\)

Work done by A, B and C together in a one hour : \(\frac{1}{8}\)

Work done by A, B and C together in one hour : \(\frac{1}{16}+\frac{1}{24}+\frac{1}{x}=\frac{5}{48}+\frac{1}{x}\)

= \(\frac{5x\,+\,48}{48x}=\frac{1}{8}\)

∴ \(\frac{5x\,+\,48}{48x}=\frac{1}{8}\)

⇒ 40X +384 = 48X 

⇒ 8X = 384

⇒ X = \(\frac{384}{8}\) = 48 hours

∴ C can do the work 48 hours.

(iv) \(6\frac{2}{3}\)

If A can do a piece of work in n days, then A can do \(\frac{1}{n}\) of the work in on day

∴ \(\frac{20}{3}=6\frac{2}{3}\) 

1. True

2. False.

Correct Statement: A compound can be broken into simpler substances chemically.

3. False.

Correct Statement: Liquid – solid colloids are called gels.

4. True

5. False.

Correct Statement: The constituents of Aspirin are present in a fixed ratio by mass. So it is a Compound

The Homo sapiens mainly hunted small animals like the wild bear, deer, mountain goat and sheep.