Oceans — Floor Relief, Salinity, Currents and Tides

Oceans cover about 71% of the Earth's surface, and the paper knows it. Physical geography questions cluster here because the answers are crisp — a depth, a salinity figure, the name of a current — which is exactly what a one-mark multiple-choice question wants.

There are five oceans: the Pacific (largest and deepest), the Atlantic (busiest for trade, S-shaped), the Indian (the only one named after a country), the Southern, and the Arctic (smallest and shallowest).

Only four things get asked, and almost nothing else: the shape of the ocean floor, how salty the water is and why that varies, which current runs where, and what makes a tide high or low. Learn those four blocks and the chapter is covered. Everything else — coral reefs, fisheries, ocean resources — hangs off them.

1. The continental shelf generally extends down to a depth of about:

2. The deepest known point on the Earth's surface, Challenger Deep, lies in which trench?

3. The average salinity of ocean water is about:

4. Which is the saltiest sea in the world?

5. Which current is chiefly responsible for keeping the ports of Norway ice-free in winter?

6. The dense fog and the rich fishing grounds of the Grand Banks off Newfoundland are produced by the meeting of:

7. A spring tide, the highest tide of the month, occurs on:

8. The highest tidal range in the world is recorded at: