Statement I: In January, in the Northern Hemisphere, the isotherms bend equatorward while crossing the landmasses, and poleward while crossing the oceans. Statement II: In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere. Which one of the following is correct?

Answer: (a) Both are correct and Statement II explains Statement I

In the northern winter, land cools fast and the sea stays warm. So a given temperature is found further north over the sea and further south over land — the isotherms bend.

The idea

An isotherm joins places with the same temperature. If a region is unusually cold for its latitude, the same temperature occurs closer to the equator there. If it is unusually warm, that temperature occurs closer to the pole. The January pattern follows the slower cooling of water.

Northern winter reduces heating → Land loses stored heat quickly → Ocean mixes and retains heat → Equal temperatures occur farther south over cold land → The same lines extend farther north over warmer water

Why the others are wrong

(b) Sees two separate facts. Ask WHY the isotherms bend — because the sea is warmer — and II becomes the explanation.

(c) Doubts II. In January the northern oceans still hold summer heat while the continents are frozen.

(d) I is correct — it is NCERT’s description of the January map.

The trap

Both statements look like two separate facts. Ask “why do the lines bend?” — because the ocean is warmer. That makes it (a).

Also know

In July, northern land generally becomes warmer than nearby oceans and the bending pattern broadly reverses. The Southern Hemisphere has less land, so its temperature lines are generally more regular. A maritime climate has a smaller annual temperature range than a continental climate. Isobars join equal pressure, not equal temperature.