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Home » UPSC Prelims Quiz » UPSC Prelims Quiz: January 13, 2026

UPSC Prelims Quiz: January 13, 2026

Q1. Nuclear fusion differs fundamentally from nuclear fission because nuclear fusion:
(a)

releases energy by splitting heavy nuclei into lighter fragments

(b)

occurs naturally only under laboratory conditions

(c)

involves the combination of light nuclei in a plasma state

(d)

does not require extremely high temperature or pressure

Explanation

(c) Correct: Fusion combines light nuclei (such as hydrogen isotopes) and occurs in the plasma state, releasing enormous energy.

(a) Incorrect: This describes nuclear fission, not fusion.

(b) Incorrect: Fusion naturally powers stars and the Sun.

(d) Incorrect: Fusion requires extremely high temperatures and pressures to sustain plasma.

Answer: (c)
Q2. Consider the following fusion-related facilities:

1. ITER

2. ADITYA

3. SST-1

Which of the following correctly matches them with their associated characteristics?

(a)

1 – India’s first tokamak; 2 – International fusion reactor; 3 – Experimental stellarator

(b)

1 – World’s largest tokamak; 2 – India’s first indigenously built tokamak; 3 – Superconducting tokamak

(c)

1 – Commercial fusion plant; 2 – Prototype reactor; 3 – Plasma heating facility

(d)

1 – European fusion reactor; 2 – Private fusion project; 3 – Experimental fission reactor

Explanation

ITER: World’s largest international tokamak project located in southern France.

ADITYA: India’s first indigenously designed and fabricated tokamak, operational since 1989 at the Institute for Plasma Research (IPR), Gujarat.

SST-1: A steady-state superconducting tokamak, fully commissioned in 2013 at IPR.

Other options: Introduce incorrect reactor types such as stellarators or fission reactors, or misclassify ownership and purpose.

Answer: (b)
Q3. With reference to the geographical features of Yemen, consider the following statements:

1. Socotra Archipelago is located in the Indian Ocean and is recognised as a UNESCO World Heritage Site.

2. Rub’ al Khali Desert extends into Yemen’s territory.

3. Yemen has no perennial rivers or natural lakes.

4. Jabal an Nabi Shu’ayb is the highest peak in the Arabian Peninsula.

Which of the statements given above are correct?

(a)

1, 2 and 3 only

(b)

1, 2 and 4 only

(c)

1, 3 and 4 only

(d)

1, 2, 3 and 4

Explanation

Statement 1 – Correct: Socotra Archipelago lies in the Indian Ocean and is recognised as a UNESCO World Heritage Site.

Statement 2 – Correct: The Rub’ al Khali (Empty Quarter) desert extends into eastern Yemen.

Statement 3 – Correct: Yemen lacks perennial rivers and natural lakes due to its arid and semi-arid climatic conditions.

Statement 4 – Correct: Jabal an Nabi Shu’ayb is the highest peak in Yemen and in the entire Arabian Peninsula.

Answer: (d)
Q4. The strategic importance of southern Yemen in global maritime trade primarily arises from its proximity to:
(a)

Strait of Hormuz

(b)

Bab el-Mandeb Strait

(c)

Bosphorus Strait

(d)

Strait of Malacca

Explanation

(b) Correct: Bab el-Mandeb Strait links the Red Sea with the Gulf of Aden and forms a critical maritime chokepoint for global shipping between Europe and Asia.

(a) Incorrect: The Strait of Hormuz connects the Persian Gulf with the Gulf of Oman.

(c) Incorrect: The Bosphorus Strait connects the Black Sea with the Mediterranean Sea.

(d) Incorrect: The Strait of Malacca lies between the Malay Peninsula and the island of Sumatra.

Answer: (b)
Q5. The Cheenkannipuzha, which drains the Aralam Butterfly Sanctuary, is a tributary of which one of the following rivers?
(a)

Bharathapuzha

(b)

Periyar

(c)

Valapattanam

(d)

Chaliyar

Explanation

(c) Correct: Cheenkannipuzha is a major tributary of the Valapattanam River system in northern Kerala.

(a), (b), (d) Incorrect: These rivers drain different physiographic regions of Kerala and are not hydrologically connected to the Aralam Butterfly Sanctuary.

Answer: (c)
Q6. With reference to the biodiversity of the Aralam Butterfly Sanctuary, consider the following statements:

1. It supports more than 250 species of butterflies.

2. Malabar Rose is an endemic butterfly species found in the sanctuary.

3. Southern Birdwing, India’s largest butterfly, occurs here.

4. The sanctuary is exclusively dedicated to invertebrate conservation and has no large mammals.

Which of the statements given above are correct?

(a)

1, 2 and 3 only

(b)

1 and 4 only

(c)

2 and 3 only

(d)

1, 2, 3 and 4

Explanation

Statement 1 – Correct: Aralam Butterfly Sanctuary is a critical habitat supporting more than 250 species of butterflies.

Statement 2 – Correct: Malabar Rose is an endemic butterfly species of the Western Ghats and is found in the sanctuary.

Statement 3 – Correct: Southern Birdwing, India’s largest butterfly, is recorded from Aralam.

Statement 4 – Incorrect: The sanctuary also supports large mammals such as elephant, tiger, gaur, sambar, and wild boar.

Answer: (a)