Discussion
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?
Answer: B
The overall air flow is downward.
Air touching the ice is cooled from 30 °C towards -7 °C. Cooler air is denser, so under gravity it sinks, and warmer air from above replaces it. The result is a natural convection current that flows down past the sphere.
Upward flow is what a hot body produces. There is motion because the temperature difference sets up buoyancy forces, and there is no sideward driving force, since gravity acts vertically.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development