Q&A: practice questions with answers

Concept: Networks are classified by geographical spread: PAN (a few metres, personal devices), LAN (one building/campus), MAN (a city), WAN (country/world, e.g. the Internet).

1. Computers in a single office building sharing files and printers over a privately owned network = Local Area Network, usually built with Ethernet/Wi-Fi switches.
2. LAN is privately managed, high-speed and low-cost; WAN/MAN use leased public telecom lines; PAN (Bluetooth) is too small for an office.

Yaad rakhein: PAN < LAN < MAN < WAN (person → building → city → world).

Answer: (D) Local Area Network (LAN)

Concept: IRENA's Renewable Energy Statistics 2026 ranks countries by total installed renewable capacity (including large hydro).

1. According to it, India stands third in the world, behind only China and the USA, having moved ahead of Brazil on the strength of record solar additions.
2. India had crossed 50% non-fossil installed capacity in 2025 and holds high ranks in solar (3rd) and wind (4th) as well.

Yaad rakhein: RE capacity 2026: China → USA → India (3rd); target 500 GW non-fossil by 2030.

Answer: (C) Third

Concept: Article 20 gives protection in respect of conviction for offences: (1) no ex-post-facto law, (2) no double jeopardy – no one shall be prosecuted and punished for the same offence more than once, (3) no self-incrimination.

1. Article 20(2) is the double-jeopardy clause asked here.
2. Article 18 = abolition of titles; 19 = six freedoms; 21 = life and personal liberty. Articles 20 and 21 cannot be suspended even during Emergency (44th Amendment).

Yaad rakhein: Art 20 = 3 protections: Ex-post-facto, Double jeopardy, Self-incrimination (E-D-S).

Answer: (A) Article 20

Concept: Under Article 317, the President may remove the UPSC Chairman/member for (a) insolvency, (b) engaging in paid employment outside the duties of office, or (c) infirmity of mind or body; for "misbehaviour" the matter must be referred to the Supreme Court.

1. Accepting a foreign award is not a ground of removal; it is not mentioned anywhere in Article 317.
2. Also, if a member is interested in a Government contract, it is deemed misbehaviour.

Yaad rakhein: UPSC removal = I-P-I (Insolvency, Paid employment, Infirmity) + misbehaviour via SC.

Answer: (B) Acceptance of foreign award

Concept: ASCII = American Standard Code for Information Interchange – a 7-bit character-encoding standard that assigns numbers 0–127 to letters, digits and symbols (e.g. 'A' = 65).

1. Extended ASCII uses 8 bits (256 characters); Unicode (UTF-8) later extended encoding to all world scripts, including Devanagari.
2. LAN = network type, RAM = memory, CD = storage medium – none is an encoding standard.

Yaad rakhein: ASCII & Unicode = character codes; 'A' = 65, 'a' = 97, '0' = 48.

Answer: (B) ASCII

Concept: The Kosi, called the "Sorrow of Bihar", is a braided Himalayan river that carries an enormous silt load from Nepal's steep catchment.

1. On entering the flat Bihar plain its velocity drops, so it deposits heavy sediment that raises and blocks its own channel; the river then shifts to a new lower course (avulsion) – it has moved about 120 km westward in 200 years.
2. It rises in the Himalayas (not Western Ghats), gets heavy monsoon rainfall and flows over soft alluvium – so the other options are false.

Yaad rakhein: Kosi = Sorrow of Bihar (silt → channel shift); Damodar = Sorrow of Bengal.

Answer: (B) It deposits heavy sediments, blocking its channel

Concept: The 61st Constitutional Amendment Act, 1988 (in force from 28 March 1989) amended Article 326 to reduce the voting age from 21 to 18 years for Lok Sabha and State Assembly elections.

1. It was passed during Rajiv Gandhi's tenure to give youth a greater say in politics.
2. 44th (1978) = removed Right to Property from Fundamental Rights; 52nd (1985) = Anti-defection (10th Schedule); 74th (1992) = Municipalities.

Yaad rakhein: 61 → 18 (voting age); 52 → defection; 42 → mini-Constitution.

Answer: (C) 61st Constitutional Amendment Act

Concept: The four Labour Codes (Wages 2019; Industrial Relations, Social Security, and Occupational Safety, Health & Working Conditions 2020) were brought into force from 21 November 2025.

1. The OSH Code allows women to work in night shifts (7 pm to 6 am) and in all types of establishments, with their consent and with safeguards – transport, security, lighting, grievance redressal.
2. The Codes do not bar women from industry, remove maternity benefits (26 weeks continue) or change retirement age.

Yaad rakhein: Labour Codes 2025 → women: night shift allowed with consent + safeguards; equal pay; gig-worker social security.

Answer: (B) Night-shift permission with safeguards

Concept: The Tribal Sub-Plan (TSP), introduced in the Fifth Five-Year Plan (1974–79), earmarks funds from Central and State budgets in proportion to the ST population for their development.

1. Its core objective is to bridge the gap between Scheduled Tribes and the rest of society in socio-economic indicators – education, health, income, infrastructure – through inclusive development and protection from exploitation.
2. It is a welfare-and-development strategy, not a scheme for private investment, urban infrastructure or industrial growth; since 2017-18 it is called Development Action Plan for STs (DAPST).

Yaad rakhein: TSP (1974) for STs & SCSP (1979) for SCs – both aim at closing the development gap.

Answer: (D) Bridge the developmental gap between Scheduled Tribes and the rest of the population through inclusive development

Concept: Sangam poems (Tamil, c. 300 BCE–300 CE) are classified into two genres – Akam (interior: love, personal emotions) and Puram (exterior: war, heroism, kings and public life).

1. Puram poems praise chieftains' valour, battles, generosity and ethics; e.g. Purananuru is a Puram anthology, while Kuruntokai is Akam.
2. The five landscapes (tinai) – kurinji, mullai, marutam, neytal, palai – structure Akam poetry.

Yaad rakhein: Akam = andar (inner, love); Puram = bahar (outer, war & public).

Answer: (A) War, valor, and public life

Concept: $\text{SP}=\text{CP}\times (1+\frac{\text{Profit}\%}{100})$; find the SP of one item, then see how many fit into ₹400.

1. CP of 1 item $=\frac{400}{20}=$ ₹20.
2. SP of 1 item at $25\%$ profit $=20\times \frac{125}{100}=$ ₹25.
3. Number of items sold for ₹400 $=\frac{400}{25}=16$.

Trick: Same money both sides → $\text{Items sold}=\text{Items bought}\times \frac{100}{100+P}=20\times \frac{100}{125}=16$.

Answer: (B) 16

Concept: When a transversal cuts two parallel lines, corresponding angles are equal, and angles on a straight line add up to ${180}^{\circ }$.

1. At M, $\angle XMA$ and $\angle AMN$ form a linear pair on line XY: $\angle AMN={180}^{\circ }-{125}^{\circ }={55}^{\circ }$.
2. $\angle AMN$ (at M, between MA and MN) and $\angle CNY$ (at N, between NC and NY) are corresponding angles for $AB\parallel CD$.
3. So $\angle CNY=\angle AMN={55}^{\circ }$.

Trick: With parallel lines every angle at the two crossings is either $x$ or ${180}^{\circ }-x$; here $x={125}^{\circ }$, so the answer must be ${55}^{\circ }$.

Answer: (C) ${55}^{\circ }$

Concept: LCM = product of the highest powers of all prime factors present in the numbers.

1. $3=3$, $77=7\times 11$, $33=3\times 11$.
2. Primes involved: 3, 7, 11 (each to power 1).
3. LCM $=3\times 7\times 11=231$.

Trick: 3 already divides 33, so LCM(3, 77, 33) = LCM(77, 33) $=\frac{77\times 33}{11}=231$.

Answer: (B) 231

Concept: Amount = Principal + Simple Interest, so $\text{SI}=\text{Amount}-\text{Principal}$ – the rate is not needed.

1. Principal = ₹620, Amount after 2 years = ₹910.
2. SI $=910-620=$ ₹290.
3. (If asked, rate $=\frac{290\times 100}{620\times 2}\approx 23.4\%$ p.a.)

Trick: Do not get distracted by "certain rate" – interest for the whole period is just $A-P$.

Answer: (A) 290

Concept: Express all shares in terms of the smallest share, add the parts and divide the total.

1. Let C $=x$. Then B $=3x$ and A $=2\times 3x=6x$.
2. Total $=6x+3x+x=10x=720\Rightarrow x=72$.
3. So C gets ₹72 (B = ₹216, A = ₹432).

Trick: A : B = 2 : 1 and B : C = 3 : 1 → A : B : C = 6 : 3 : 1; C's share $=\frac{1}{10}\times 720=72$.

Answer: (C) ₹72

Concept: Dividend $=\text{Divisor}\times \text{Quotient}+\text{Remainder}$.

1. Remainder $=12$; divisor $=8\times 12=96$.
2. Divisor $=3\times$ quotient $\Rightarrow$ quotient $=\frac{96}{3}=32$.
3. Dividend $=96\times 32+12=3072+12=3084$.

Trick: $96\times 32=96\times 30+96\times 2=2880+192=3072$; add the remainder 12 → 3084 (ends in 4, so options A/C/D are out).

Answer: (B) 3084

Concept: Variance ${\sigma }^2=\frac{\sum x_i^2}{n}-{\overline{x}}^2$ (population variance, $n=6$).

1. $\sum x=4+8+6+5+3+9=35$, so $\overline{x}=\frac{35}{6}$.
2. $\sum x^2=16+64+36+25+9+81=231$.
3. ${\sigma }^2=\frac{231}{6}-{\left(\frac{35}{6}\right)}^2=\frac{231\times 6-1225}{36}=\frac{1386-1225}{36}=\frac{161}{36}$.

Trick: Keep the mean as a fraction ($\frac{35}{6}$) instead of a decimal; the denominator 36 appears directly, which eliminates options B and D.

Answer: (C) $\frac{161}{36}$

Concept: If gain is $40\%$ on CP, then $\text{SP}=\frac{140}{100}\times \text{CP}$, so $\text{Profit}=\frac{40}{140}\times \text{SP}=\frac{2}{7}\times \text{SP}$.

1. Sale proceeds (SP) = ₹3,955.
2. CP $=3955\times \frac{100}{140}=\frac{3955}{1.4}=$ ₹2,825.
3. Profit $=3955-2825=$ ₹1,130.

Trick: Profit $=\frac{2}{7}\times 3955=2\times 565=1130$ (since $3955÷7=565$).

Answer: (A) 1,130

Concept: Area of triangle $=\frac{1}{2}\times \text{base}\times \text{height}$; the square's area is twice this.

1. Triangle area $=\frac{1}{2}\times 23\times 12=138{\text{cm}}^2$.
2. Square area $=2\times 138=276{\text{cm}}^2$.
3. (Its side would be $\sqrt{276}\approx 16.6$ cm, but only the area is asked.)

Trick: Twice the triangle's area is simply $\text{base}\times \text{height}=23\times 12=276$ – no halving needed.

Answer: (D) $276{\text{cm}}^2$

Concept: Divide the whole equation by $\sin y$ to get $\cot y$, then invert and rationalise.

1. $5\sin y+\cos y=\sqrt{13}\sin y\Rightarrow \cos y=(\sqrt{13}-5)\sin y$.
2. $\tan y=\frac{\sin y}{\cos y}=\frac{1}{\sqrt{13}-5}$.
3. Rationalise: $\frac{1}{\sqrt{13}-5}\times \frac{\sqrt{13}+5}{\sqrt{13}+5}=\frac{\sqrt{13}+5}{13-25}=\frac{\sqrt{13}+5}{-12}=\frac{-5-\sqrt{13}}{12}$.

Trick: Since $\sqrt{13}<5$, $\cos y$ and $\sin y$ have opposite signs, so $\tan y$ must be negative with denominator $25-13=12$ – only option C matches.

Answer: (C) $\frac{-5-\sqrt{13}}{12}$