With reference to the distribution of isotherms in January, consider the following statements: 1. In the Northern Hemisphere, isotherms deviate to the north over the ocean. 2. In the Northern Hemisphere, isotherms deviate to the north over the continent. 3. The deviation of isotherms is more pronounced in the Northern Hemisphere than in the Southern Hemisphere. Which of the statements given above is/are correct?

Correct Option The correct option is 1 and 3 only. Explanation Isotherms are imaginary lines connecting places having equal temperatures. Their distribution is significantly influenced by the differential heating and cooling of land and water bodies. In January, it is winter in the Northern Hemisphere and summer in the Southern Hemisphere. The presence of vast landmasses in the Northern Hemisphere creates distinct temperature contrasts compared to the oceans. Statement-wise Analysis - Statement 1 is Correct: In January, the Northern Hemisphere experiences winter. During this season, the land surface cools more rapidly than the oceans. Consequently, the oceans are warmer than the continents at the same latitude. To connect points of equal temperature, an isotherm must shift poleward (to the north) over the warmer ocean to reach the latitude where the temperature drops sufficiently to match the land temperature. Thus, isotherms bend to the north over the Atlantic and Pacific oceans. - Statement 2 is Incorrect: Over the continents in the Northern Hemisphere during January, temperatures are significantly lower than over the adjacent oceans. To maintain the same temperature value, the isotherm must shift towards the equator (to the south) to find warmer conditions. Therefore, isotherms deviate to the south over the continents, not to the north. - Statement 3 is Correct: The Northern Hemisphere contains a much larger proportion of landmass compared to the Southern Hemisphere, which is predominantly covered by oceans. The strong contrast between land and water temperatures in the Northern Hemisphere causes isotherms to deviate significantly (zigzag pattern). In contrast, the Southern Hemisphere exhibits more regular isotherms that run largely parallel to the latitudes due to the uniform influence of the oceans. Key Takeaway Key Takeaway: During winter, isotherms bend poleward over warmer oceans and equatorward over colder continents. This deviation is far more pronounced in the Northern Hemisphere due to the extensive land-water contrast, whereas isotherms in the Southern Hemisphere are relatively straight.

With reference to the distribution of isotherms in… - NCERT Class 11 Geography MCQ

NCERT Class 11 Geography — Chapter 2: Solar radiation, heat balance and temperature

mcqmedium

With reference to the distribution of isotherms in January, consider the following statements:

In the Northern Hemisphere, isotherms deviate to the north over the ocean.
In the Northern Hemisphere, isotherms deviate to the north over the continent.
The deviation of isotherms is more pronounced in the Northern Hemisphere than in the Southern Hemisphere.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Fundamentals of Physical Geography · Page 5

Options

A1 and 3 only
B1, 2 and 3
C2 only
D1 and 2 only

Did you get this right?

Solution

Correct Option

The correct option is 1 and 3 only.

Explanation

Isotherms are imaginary lines connecting places having equal temperatures. Their distribution is significantly influenced by the differential heating and cooling of land and water bodies. In January, it is winter in the Northern Hemisphere and summer in the Southern Hemisphere. The presence of vast landmasses in the Northern Hemisphere creates distinct temperature contrasts compared to the oceans.

Statement-wise Analysis

Statement 1 is Correct: In January, the Northern Hemisphere experiences winter. During this season, the land surface cools more rapidly than the oceans. Consequently, the oceans are warmer than the continents at the same latitude. To connect points of equal temperature, an isotherm must shift poleward (to the north) over the warmer ocean to reach the latitude where the temperature drops sufficiently to match the land temperature. Thus, isotherms bend to the north over the Atlantic and Pacific oceans.
Statement 2 is Incorrect: Over the continents in the Northern Hemisphere during January, temperatures are significantly lower than over the adjacent oceans. To maintain the same temperature value, the isotherm must shift towards the equator (to the south) to find warmer conditions. Therefore, isotherms deviate to the south over the continents, not to the north.
Statement 3 is Correct: The Northern Hemisphere contains a much larger proportion of landmass compared to the Southern Hemisphere, which is predominantly covered by oceans. The strong contrast between land and water temperatures in the Northern Hemisphere causes isotherms to deviate significantly (zigzag pattern). In contrast, the Southern Hemisphere exhibits more regular isotherms that run largely parallel to the latitudes due to the uniform influence of the oceans.

Key Takeaway

Key Takeaway: During winter, isotherms bend poleward over warmer oceans and equatorward over colder continents. This deviation is far more pronounced in the Northern Hemisphere due to the extensive land-water contrast, whereas isotherms in the Southern Hemisphere are relatively straight.

Your note

More from Chapter 2: Solar radiation, heat balance and temperature

Consider the following statements regarding the insolation received at the Earth's surface: 1. Generally, at the same latitude, insolation is more over the continent than over the oceans. 2. In winter, the middle and higher latitudes receive more radiation than in summer. 3. The subtropical deserts receive more insolation than the equator. Which of the statements given above is/are correct?

medium

Which of the following is a characteristic of the isotherms in the Southern Hemisphere?

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With reference to the specific heat of land and water, consider the following statements: 1. The variation in temperature over the sea is much greater compared to land. 2. Land heats up and cools down more quickly than the sea. 3. Places near the sea experience extreme temperature variations. Which of the statements given above is/are correct?

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Which of the following is defined as "the energy needed to raise the temperature of one gram of substance by one Celsius"?

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In the context of the heat budget, what percentage of incoming solar radiation is reflected back to space before reaching the earth's surface?

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