Out of the following which combination is incorrect ?
- (a)Telegraph Plateau - Indian Ocean
- (b)Cocoa Ridge - Pacific Ocean
- (c)Walvis Ridge - Atlantic Ocean
- (d)Agulhas Basin - Indian Ocean
Correct — A, 'Telegraph Plateau – Indian Ocean' is the incorrect combination. The Telegraph Plateau is a relatively shallow submarine rise in the North Atlantic Ocean, between Newfoundland and Ireland, along which the first transatlantic telegraph cable was laid in 1858 — so tying it to the Indian Ocean is wrong. The other three are correctly matched: the Cocos Ridge (the paper prints 'Cocoa') lies in the eastern Pacific, the Walvis Ridge in the South Atlantic off Namibia, and the Agulhas Basin in the southern Indian Ocean off South Africa.
- (b)Cocoa Ridge - Pacific Ocean — This pairing is correct: the Cocos Ridge is an aseismic ridge in the eastern Pacific Ocean (on the Cocos Plate, off Central America), so it is not the mismatch.
- (c)Walvis Ridge - Atlantic Ocean — Correct pairing: the Walvis Ridge is a major aseismic ridge in the South Atlantic Ocean, running from off Namibia toward Tristan da Cunha — not the mismatch.
- (d)Agulhas Basin - Indian Ocean — Correct pairing: the Agulhas Basin lies in the southern Indian Ocean off the southern tip of South Africa — not the mismatch.
This tests ocean-floor relief features (ridges, plateaus and basins) and the oceans they belong to. 'Telegraph Plateau' is historically famous as the North Atlantic route of the first transatlantic cable — the giveaway that it is Atlantic, not Indian. Cocos Ridge (Pacific), Walvis Ridge (South Atlantic) and Agulhas Basin (southern Indian Ocean) are standard oceanography associations.
In a 'which pairing is incorrect' set you only need to find the single mismatch. The Telegraph Plateau's very name recalls the 1858 Atlantic cable, so pairing it with the Indian Ocean stands out as wrong; the remaining three are standard, correctly placed features.
- Telegraph Plateau: North Atlantic Ocean — route of the first transatlantic telegraph cable (1858)
- Cocos Ridge: eastern Pacific Ocean (Cocos Plate, off Central America)
- Walvis Ridge: South Atlantic Ocean (off Namibia)
- Agulhas Basin: southern Indian Ocean (off South Africa)
Only Telegraph Plateau is misplaced — it lies in the North Atlantic, not the Indian Ocean.
- Guessing a feature's ocean without an anchor fact
- Forgetting that the Telegraph Plateau is an Atlantic (cable-route) feature
UPSC and MPPSC give match-the-feature-to-the-ocean lists, or ask 'which pair is incorrect'.
Match List I (Oceanic Trench) — I. Aleutian, II. Kermadec, III. Sunda, IV. S. Sandwich — with List II (Location) — A) Indian Ocean, B) North Pacific Ocean, C) South Pacific Ocean, D) South Atlantic Ocean — and select the correct answer using the codes given below the Lists.
- (a) I-B, II-D, III-A, IV-C
- (b) I-B, II-C, III-A, IV-D
- (c) I-A, II-C, III-B, IV-D
- (d) I-A, II-D, III-B, IV-C
Answer(b) I-B, II-C, III-A, IV-D — Aleutian→N Pacific, Kermadec→S Pacific, Sunda→Indian, S. Sandwich→S Atlantic.
Same concept — matching submarine relief features (there trenches) to the oceans they lie in.
In which one of the following oceans is Diamantina Trench situated?
- (a) Pacific Ocean
- (b) Atlantic Ocean
- (c) Indian Ocean
- (d) Arctic Ocean
Answer(c) Indian Ocean — the Diamantina Trench lies in the south-eastern Indian Ocean.
Same idea — placing an ocean-floor feature in the correct ocean.
The Ninety East Ridge (90° East Ridge) is located in which of the following oceans?
- (a) Arctic Ocean
- (b) Atlantic Ocean
- (c) Pacific Ocean
- (d) Indian Ocean
Answer(d) Indian Ocean
MPPSC tested the same skill — identifying the ocean of a named submarine ridge.
- practice — not a real PYQ
The first transatlantic telegraph cable (1858) was laid across a shallow submarine rise, the Telegraph Plateau, located in the
- (a)North Atlantic Ocean
- (b)Indian Ocean
- (c)Pacific Ocean
- (d)Arctic Ocean
Answer(a) North Atlantic Ocean — between Newfoundland and Ireland.
- practice — not a real PYQ
The Walvis Ridge, an aseismic ridge off the coast of Namibia, lies in which ocean?
- (a)Indian Ocean
- (b)South Atlantic Ocean
- (c)North Pacific Ocean
- (d)Arctic Ocean
Answer(b) South Atlantic Ocean — running from off Namibia toward Tristan da Cunha.