With reference to “Coriolis force”, which of the following statements is/are correct?

1. It increases with increase in wind velocity.

2. It is maximum at the poles and is absent at the equator.

Select the answer using the code given below.

The correct answer is Both 1 and 2.

Let us understand the Coriolis force and analyze the statements step-by-step to explain why both of them are correct:

1. Understanding the Coriolis Force:
The Coriolis force is an apparent or fictitious force that acts on objects in motion relative to a rotating reference frame, such as the Earth. It deflects the path of winds and ocean currents—to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

2. Analysis of Statement 1: "It increases with increase in wind velocity."
The magnitude of the Coriolis force per unit mass is mathematically expressed as:
$$F=2·v·\omega ·\sin \left(\phi \right)$$
where:
• _$v$ is the wind velocity (speed of the moving air),
• _$\omega$ is the angular velocity of the Earth's rotation, and
• _$\phi$ is the latitude.
Since the Coriolis force (_$F$) is directly proportional to the wind velocity (_$v$), any increase in wind speed results in a proportional increase in the Coriolis force. Therefore, Statement 1 is correct.

3. Analysis of Statement 2: "It is maximum at the poles and is absent at the equator."
The Coriolis force is also directly dependent on the sine of the latitude (_{$\sin \left(\phi \right)$}):
• At the equator: The latitude _{$\phi =0°$}. Since _{$\sin (0°)=0$}, the Coriolis force is zero (absent) at the equator.
• At the poles: The latitude _{$\phi =90°$}. Since _{$\sin (90°)=1$} (which is the maximum value for the sine function), the Coriolis force reaches its maximum value at the poles.
Therefore, Statement 2 is correct.

Since both Statement 1 and Statement 2 are correct, the appropriate option is Both 1 and 2.