Question

What is the primary cause of the Coriolis Effect?

• A. Earth's revolution around the Sun
• B. Earth's rotation on its axis
• C. Gravitational pull of the Moon
• D. Uneven heating of the Earth's surface

Hint:

Remember the rule of the Coriolis Effect:

• \textbf{Northern Hemisphere} $\rightarrow$ Deflection to the \textbf{right}
• \textbf{Southern Hemisphere} $\rightarrow$ Deflection to the \textbf{left}

\textbf{Cause:} Rotation of the Earth.

Answer 1

The Correct Option is B

Concept: The Coriolis Effect refers to the apparent deflection of moving objects such as winds, ocean currents, and projectiles due to the rotation of the Earth. It is a key concept in physical geography and meteorology because it influences global wind systems and ocean circulation. When the Earth rotates from west to east, objects moving over its surface do not travel in a straight line relative to the rotating planet. Instead, their paths appear to curve.

• In the Northern Hemisphere, moving objects are deflected toward the right.
• In the Southern Hemisphere, moving objects are deflected toward the left.

This phenomenon is known as the Coriolis Effect, named after the French scientist Gaspard-Gustave Coriolis.
Step 1: Understanding the cause of the Coriolis Effect.
The Earth rotates on its axis once every 24 hours. Because of this rotation, different parts of the Earth move at different speeds:

• The equator moves faster because it has a larger circumference.
• The polar regions move slower.

When air masses or ocean currents move across the Earth’s surface, the difference in rotational speed causes their paths to deflect.
Step 2: Impact of the Coriolis Effect.
The Coriolis Effect influences many global phenomena, including:

• Global wind systems such as the trade winds and westerlies
• Ocean currents
• Cyclones and anticyclones

For example, cyclones rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere due to the Coriolis Effect.
Step 3: Evaluating the options.

• Earth's revolution around the Sun: Responsible for seasons, not the Coriolis Effect.
• Earth's rotation on its axis: The primary cause of the Coriolis Effect. (Correct)
• Gravitational pull of the Moon: Mainly responsible for tides.
• Uneven heating of the Earth's surface: Causes wind generation but not the Coriolis deflection.

Thus, the correct answer is: \[ \text{Earth's rotation on its axis} \]