Which one of the following rivers is not a tributary of river Brahmaputra?
- (a)River Manas
- (b)River Kameng
- (c)River Mahananda
- (d)River Subansiri
Correct — C, River Mahananda. The Mahananda rises in the Darjeeling Himalaya and flows south to join the Ganga (Ganges) system — it is a tributary of the Ganga, not the Brahmaputra. Manas, Kameng and Subansiri are all Himalayan tributaries that feed the Brahmaputra in Assam/Arunachal Pradesh, so Mahananda is the one that does not belong.
- (a)River Manas — The Manas rises in Bhutan/Tibet and is a major north-bank tributary of the Brahmaputra in Assam, so it is correctly a Brahmaputra tributary.
- (b)River Kameng — The Kameng flows from Arunachal Pradesh and joins the Brahmaputra (as the Jia Bhoroli in Assam); it is a genuine Brahmaputra tributary.
- (d)River Subansiri — The Subansiri is the largest tributary of the Brahmaputra, rising in Tibet and flowing through Arunachal Pradesh into Assam — clearly a Brahmaputra tributary.
The Brahmaputra rises in Tibet as the Tsangpo, takes a great U-turn near Namcha Barwa, and enters India in Arunachal Pradesh as the Siang/Dihang. In Assam it is fed by numerous Himalayan tributaries from the north (e.g., Subansiri, Kameng, Manas, Dhansiri) and some from the south. The Mahananda, however, belongs to the Ganga system, draining the Darjeeling hills and north Bengal.
The trap is that Manas, Kameng, Subansiri and Mahananda are all north-eastern/eastern Himalayan rivers, so all four 'sound' like Brahmaputra feeders. The discriminator is that the Mahananda drains west into the Ganga, while the other three join the Brahmaputra.
- The Subansiri is the largest tributary of the Brahmaputra.
- Kameng (Jia Bhoroli), Manas and Subansiri are north-bank Brahmaputra tributaries from Arunachal/Bhutan.
- The Mahananda rises in the Darjeeling Himalaya and is a tributary of the Ganga.
- The Brahmaputra is called the Tsangpo in Tibet and the Siang/Dihang on entering India.
- Assuming any north-eastern Himalayan river must be a Brahmaputra tributary — the Mahananda joins the Ganga.
- Confusing tributaries of the Brahmaputra with those of the Barak/Meghna system in the region.
Asked as 'which is not a tributary of river X', or through tributary–main-river matching pairs.
Consider the following pairs: Tributary River – Main River 1. Chambal : Narmada 2. Sone : Yamuna 3. Manas : Brahmaputra. Which of the pairs given above is/are correctly matched?
- (a) 1, 2 and 3
- (b) 1 and 2 only
- (c) 2 and 3 only
- (d) 3 only
Answer(d) 3 only — only Manas : Brahmaputra is correct; Chambal joins the Yamuna and the Sone joins the Ganga.
Same concept — matching tributaries to their main rivers, and confirming that the Manas is a Brahmaputra tributary (as in this question).
Consider the following statements regarding River Brahmaputra: 1. It rises in Tibet, near Lake Mansarovar 2. It takes a "U" turn near Namcha Barwa and enters India through a gorge Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer(c) Both 1 and 2
Same river system — the Brahmaputra's course and character, the framework for knowing which Himalayan rivers are its tributaries.
- practice — not a real PYQ
Which one of the following is the largest tributary of the Brahmaputra?
- (a)Manas
- (b)Subansiri
- (c)Kameng
- (d)Dhansiri
Answer(b) Subansiri — it is the Brahmaputra's largest tributary, rising in Tibet and flowing through Arunachal Pradesh.
- practice — not a real PYQ
The River Mahananda is a tributary of which of the following rivers?
- (a)Brahmaputra
- (b)Ganga
- (c)Barak
- (d)Teesta
Answer(b) Ganga — the Mahananda drains the Darjeeling Himalaya and joins the Ganga system.