Let a spherical block of ice at-7 °C be exposed to atmospheric air at 30 °C with the gravitational direction as shown in the figure below. What will be the overall direction of air flow in this situation?

The correct option is Downward.

Step-by-Step Explanation:

1. Analysis of the Setup from the Diagram:
The provided image shows a spherical Ice block at -7 °C surrounded by Air at 30 °C (labeled both above and below the block). On the right side of the diagram, a vertical arrow labeled Gravity points downwards. On the left side, directional arrows are shown indicating Upward, Downward, and Sideward directions.

2. Heat Transfer Process:
Since the temperature of the ice block is -7 °C and the ambient air is at 30 °C, there is a temperature difference. Heat naturally flows from the warmer air to the colder ice block. This cooling effect lowers the temperature of the air layer in immediate contact with the ice block.

3. Density Change:
For a gas like air, the density is inversely proportional to its absolute temperature under constant pressure. This relationship is described by the ideal gas law equation:
$$\rho =\frac{P}{RT}$$
Where:
- $\rho$ represents the density of the air
- $P$ represents the pressure
- $R$ represents the specific gas constant of air
- $T$ represents the absolute temperature
As the temperature of the air near the ice block decreases ($T_{\text{local}}<T_{\text{ambient}}$), its local density increases (${\rho }_{\text{local}}>{\rho }_{\text{ambient}}$). This makes the cooled air heavier than the surrounding warmer air.

4. Gravity and Flow Direction:
Because the gravity vector points downwards, the gravitational force acting on the denser, colder air is stronger than the buoyant force exerted by the warmer, less dense air surrounding it. Consequently, this heavier air sinks under gravity, creating a natural convection current that flows in the Downward direction.