Class 11 Geography Important Chapter 17 Air Circulation and Weather

Class 11 Geography Important Chapter 17 Air Circulation and Weather Solutions English Medium As Per AHSEC New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters ASSEB Class 11 Geography Important Solutions and select need one. AHSEC Class 11 Elective Geography Additional Notes English Medium Download PDF. HS 1st Year Finance Important Solutions in English.

Class 11 Geography Important Chapter 17 Air Circulation and Weather

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. ASSEB Class 11 Elective Geography Additional Question Answer are part of All Subject Solutions. Here we have given HS 1st Year Elective Geography Important Notes in English for All Chapters, You can practice these here.

Air Circulation and Weather

Chapter: 17

FOURTH UNIT: ATMOSPHERE, WEATHER AND CLIMATE

IMPORTANT QUESTION AND ANSWER

Answer The Following Questions:

1. How is a cell formed?

Ans: The process of oceanic heating advances gradually through the convection system. During the day, due to equal solar radiation, the land near the coast becomes warmer than the sea surface. As a result, the air above the land becomes hot and light, rising upward and creating a local low-pressure cell.

2. What is a local wind?

Ans: Winds that develop within a small regional area due to heating and cooling of the earth’s surface within a short period (usually within 24 hours) are called local winds. These winds originate and move within a limited geographical region.

3. What are the main factors responsible for the origin and intensification of tropical cyclones?

Ans: The main factors are five in number:

(i) Vast sea surface with a temperature above 27°C.

(ii) Effect of Coriolis force.

(iii) Uniform upward movement of air.

(iv) Overall low-pressure condition at the origin site.

(v) Divergent flow of air at upper levels.

4. What is lightning?

Ans: The striking of an electric charge from a strong cloud mass toward the earth is called lightning or thunderstroke.

5. What is Hadley’s Cell?

Ans: The air circulation cell formed between the Equator and 30° latitude is called the Hadley Cell.

6. What is trade wind?

Ans: The permanent wind that blows from 30° latitude toward the Equator as part of the Hadley Cell is called the trade wind.

7. Write the full form of ENSO.

Ans: The full form of ENSO is El-Nino Southern Oscillation.

8. What is a katabatic wind?

Ans: The wind that blows from snow-covered plateaus toward warm valleys is called a katabatic wind or descending wind.

9. What is the name of the wind that flows from the high-pressure area at mountain tops to low-pressure areas at the foothills during the night?

Ans: The wind flowing from the mountain top toward the valley during the night is called the mountain wind.

10. Where does a cyclone form?

Ans: A cyclone forms at the center of a low-pressure area.

Long Question & Answer:

1. Describe the effects of pressure gradient force, frictional force, and Coriolis force on the wind.

Ans: Three main forces act on air circulation over the earth—pressure gradient force, frictional force, and Coriolis force. The combined effect of these forces determines the direction and speed of wind.

(i) Pressure Gradient Force: It means the difference in air pressure between two places. Air moves from high-pressure areas to low-pressure areas. The greater the difference, the faster the wind speed. Hence, it is the primary source of wind.

(ii) Frictional Force: Friction arises due to the contact of air with the earth’s surface, slowing down wind speed. Over rough terrain (mountains, forests), friction is high, whereas it is less over smooth sea surfaces. Generally, this force acts up to 1–3 km above the surface.

(iii) Coriolis Force: Caused by the earth’s rotation, it deflects the movement of air. In the Northern Hemisphere, winds turn to the right, while in the Southern Hemisphere, they turn to the left. At the equator, the Coriolis force is zero. Due to this force, winds move in curved paths instead of straight lines.