Wind Energy, Coriolis Force, Trade Winds and Beaufort Number
Complete Notes for Competitive Examinations
By Home Academy
1. Wind Energy
Definition
Wind energy is the energy possessed by moving air.
It is a:
Renewable source of energy
Non-conventional source of energyPollution-free source of energy
Wind energy is mainly caused due to:
Uneven heating of Earth by Sun
Rotation of EarthPressure differences in atmosphere
2. Formation of Wind
Air moves from:
High pressure area → Low pressure areaThis movement of air is called wind.
Cause of Wind Formation
| Cause | Explanation |
|---|---|
| Unequal heating | Different temperatures create pressure differences |
| Rotation of Earth | Deflects wind direction |
| Atmospheric pressure | Controls movement of air |
3. Wind Energy Conversion
Wind energy is converted into electrical energy using windmills or wind turbines.
Energy Conversion
Wind\ Energy \rightarrow Mechanical\ Energy \rightarrow Electrical\ Energy
4. Windmill / Wind Turbine
Definition
A machine that converts kinetic energy of wind into electrical energy.
Main Parts of Wind Turbine
| Part | Function |
|---|---|
| Blades | Rotate due to wind |
| Rotor | Transfers motion |
| Generator | Produces electricity |
| Tower | Supports turbine |
Working of Wind Turbine
Wind strikes blades.
Blades rotate.
Rotor rotates generator.
Electricity is produced.
5. Advantages of Wind Energy
| Advantage | Explanation |
|---|---|
| Renewable | Unlimited source |
| Pollution free | No harmful gases |
| No fuel cost | Wind is free |
| Eco-friendly | Sustainable energy |
6. Disadvantages of Wind Energy
| Disadvantage | Explanation |
|---|---|
| Depends on wind speed | Irregular supply |
| Large land required | Wind farms occupy area |
| Noise pollution | Turbine sound |
| Expensive installation | High setup cost |
7. Important Wind Energy Areas in India
| State | Important Area |
|---|---|
| Tamil Nadu | Muppandal |
| Gujarat | Coastal areas |
| Rajasthan | Desert regions |
| Maharashtra | Satara |
Important Point
Tamil Nadu is a leading wind energy producer in India.
8. Coriolis Force
Definition
An apparent force caused by Earth’s rotation that deflects moving objects including winds.
Discoverer
Named after:
Gaspard-Gustave de Coriolis
Direction of Deflection
| Hemisphere | Deflection |
|---|---|
| Northern Hemisphere | Right |
| Southern Hemisphere | Left |
Important Concept
Coriolis force affects:
Wind direction
Ocean currentsCyclones
Important Point
Coriolis force is maximum at poles and zero at equator.
9. Trade Winds
Definition
Permanent winds blowing from subtropical high-pressure belts toward equatorial low-pressure belt.
Direction of Trade Winds
| Hemisphere | Direction |
|---|---|
| Northern Hemisphere | North-East Trade Winds |
| Southern Hemisphere | South-East Trade Winds |
Cause of Trade Winds
Pressure difference
Coriolis forceEarth’s rotation
Characteristics of Trade Winds
| Feature | Description |
|---|---|
| Permanent winds | Blow throughout year |
| Steady direction | Predictable |
| Warm winds | Tropical origin |
Importance of Trade Winds
Help in navigation
Influence rainfallAffect climate
10. Westerlies
Definition
Winds blowing from west to east in middle latitudes.
11. Polar Winds
Cold winds blowing from poles toward subpolar low-pressure regions.
12. Beaufort Scale / Beaufort Number
Definition
A scale used to measure wind speed based on observed effects.
Developed By
Francis Beaufort
Range
| Beaufort Number | Wind Condition |
|---|---|
| 0 | Calm |
| 1–3 | Light breeze |
| 4–6 | Moderate breeze |
| 7–9 | Strong wind |
| 10–12 | Storm/Hurricane |
Important Point
Higher Beaufort number indicates stronger wind.
Beaufort Scale Table
| Beaufort No. | Wind Type | Speed (Approx.) |
|---|---|---|
| 0 | Calm | <1 km/h |
| 1 | Light air | 1–5 km/h |
| 2 | Light breeze | 6–11 km/h |
| 3 | Gentle breeze | 12–19 km/h |
| 4 | Moderate breeze | 20–28 km/h |
| 5 | Fresh breeze | 29–38 km/h |
| 6 | Strong breeze | 39–49 km/h |
| 7 | Near gale | 50–61 km/h |
| 8 | Gale | 62–74 km/h |
| 9 | Strong gale | 75–88 km/h |
| 10 | Storm | 89–102 km/h |
| 11 | Violent storm | 103–117 km/h |
| 12 | Hurricane | >118 km/h |
13. Applications of Wind Energy
| Application | Use |
|---|---|
| Electricity generation | Wind turbines |
| Water pumping | Rural areas |
| Sailing ships | Transportation |
| Grinding grains | Traditional windmills |
14. Important Exam Points
Wind energy is renewable.
Wind forms due to pressure differences.Coriolis force due to Earth’s rotation.
Northern Hemisphere winds deflect right.
Southern Hemisphere winds deflect left.
Trade winds blow toward equator.
Beaufort scale measures wind speed.
Beaufort number 0 indicates calm condition.
Beaufort number 12 indicates hurricane.
15. Frequently Asked MCQs
1. Wind energy is:
A. Non-renewable
B. Renewable
C. Fossil fuel
D. Nuclear energy
✅ Answer: B
2. Coriolis force is caused due to:
A. Revolution of Earth
B. Gravity of Moon
C. Rotation of Earth
D. Ocean currents
✅ Answer: C
3. In Northern Hemisphere winds deflect toward:
A. Left
B. Right
C. Upward
D. Downward
✅ Answer: B
4. Beaufort scale measures:
A. Temperature
B. Rainfall
C. Wind speed
D. Humidity
✅ Answer: C
5. Beaufort number 0 represents:
A. Hurricane
B. Storm
C. Calm
D. Gale
✅ Answer: C
6. Trade winds blow toward:
A. Poles
B. Equator
C. Mountains
D. Oceans
✅ Answer: B
16. Fact-Based Questions
Question 1
Consider the following statements:
Wind energy is renewable.
Coriolis force is due to Earth’s rotation.
Beaufort scale measures wind speed.
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
Question 2
Which of the following statements are correct?
Northern Hemisphere winds deflect right.
Southern Hemisphere winds deflect left.
Coriolis force is zero at equator.
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
Question 3
Consider the following:
Trade winds are permanent winds.
Beaufort number 12 indicates hurricane.
Wind turbines generate electricity.
A. Only 1 and 2
B. Only 2 and 3
C. 1, 2 and 3
D. Only 1 and 3
✅ Answer: C
17. Assertion–Reason Questions
Assertion (A)
Trade winds do not move in straight direction.
Reason (R)
Coriolis force deflects moving winds due to Earth’s rotation.
A. Both A and R are true and R explains A
B. Both true but R not explanation
C. A true, R false
D. A false, R true
✅ Answer: A
Assertion (A)
Wind energy is considered eco-friendly.
Reason (R)
It produces very little air pollution.
A. Both A and R are true and R explains A
B. Both true but R not explanation
C. A true, R false
D. A false, R true
✅ Answer: A
18. Previous Year Type Questions (PYQs)
PYQ 1
The force responsible for deflection of winds is:
A. Gravitational force
B. Magnetic force
C. Coriolis force
D. Frictional force
✅ Answer: C
PYQ 2
Trade winds blow from:
A. Equator to poles
B. Poles to equator
C. Subtropical highs toward equator
D. Mountains toward plains
✅ Answer: C
PYQ 3
Beaufort scale is used for measuring:
A. Earthquake intensity
B. Wind speed
C. Temperature
D. Humidity
✅ Answer: B
19. Quick Revision Table
| Topic | Important Fact |
|---|---|
| Wind energy | Renewable |
| Coriolis force | Due to Earth rotation |
| Northern Hemisphere | Deflection to right |
| Southern Hemisphere | Deflection to left |
| Beaufort scale | Measures wind speed |
| Beaufort No. 12 | Hurricane |
20. One-Liner Revision
| Question | Answer |
|---|---|
| Cause of wind | Pressure difference |
| Force deflecting winds | Coriolis force |
| Beaufort scale measures | Wind speed |
| Beaufort number for calm | 0 |
| Beaufort number for hurricane | 12 |
| Direction of trade winds | Toward equator |
Conclusion
Wind energy is an important renewable source generated due to movement of air caused by unequal heating and Earth’s rotation. Coriolis force controls wind direction, trade winds are major permanent winds, and the Beaufort scale measures wind speed intensity. These concepts are extremely important for competitive examinations and environmental science.
Prepared By Home Academy