CAPF AC 2020 Q68: Geography – Physical Geography & Geomorphology
Which one of the following karst landforms is the largest in size ?
- (a) Polje
- (b) Uvala
- (c) Swallow Hole
- (d) Sink Hole
Answer: (a) Polje
Explanation
Karst landforms by size
How to think: karst hollows grow by joining together.
Small holes merge into bigger ones.
So put the four in order of size.
| Landform | How it forms | Size |
|---|---|---|
| Swallow hole | Opening where a stream disappears underground | Smallest |
| Sink hole | Funnel-shaped hollow made by solution of limestone | Small |
| Uvala | Several sink holes or dolines join | Large |
| Polje | Several uvalas join; a long, flat-floored basin | Largest |
Karst features:
| Type | Examples |
|---|---|
| On the surface | Lapies, sink holes, dolines, uvalas, poljes |
| Underground | Caves, stalactites (hang from the roof), stalagmites (rise from the floor) |
Karst forms in limestone regions.
The name comes from the Karst region near the Adriatic Sea.
Answer: (a) Polje.
Why each option is right or wrong
- (a) CORRECT. A polje is the largest karst depression, often many kilometres long.
- (b) Incorrect. An uvala is large, but smaller than a polje.
- (c) Incorrect. A swallow hole is only the opening where a stream goes underground.
- (d) Incorrect. A sink hole is a small funnel-shaped hollow.
Key point
Karst depressions in rising order of size: swallow hole and sink hole, doline, uvala, polje. Formed by solution of limestone.
Remember
Polje is the largest karst hollow.
Common mistakes
- Swapping uvala and polje; the polje is the bigger one.
- Mixing up stalactites (from the ceiling) with stalagmites (from the ground).
- Thinking karst forms in granite; it needs soluble rock like limestone.
Exam tip
Small to big: sink hole, doline, uvala, polje. The last in the list is the largest.
Sources
- NCERT Class XI Geography — Fundamentals of Physical Geography (Landforms and their Evolution: groundwater)
- G. C. Leong — Certificate Physical and Human Geography (Limestone and Chalk Landforms)