List-I List-II P. Cupping 1. Caused by wood limbs encased by wood of the free trunk Q. Bowing 2. Caused by grain irregularities in the board R. Checks 3. Small cracks appearing at the ends of boards due to rapid drying S. Knots 4. Unequal shrinking in the radial and tangential direction
| P | Q | R | S |
| 4 | 2 | 3 | 1 |
Wood Defect Matching Solution
The question requires matching common wood defects presented in List-I with their corresponding causes or descriptions found in List-II.
Analyzing the Matches
Here's a breakdown of the correct matches:
- P. Cupping is matched with 4. Unequal shrinking in the radial and tangential direction. This is because cupping occurs due to differential shrinkage across the width of the wood.
- Q. Bowing is matched with 2. Caused by grain irregularities in the board. Grain irregularities often lead to internal stresses that cause bowing.
- R. Checks are matched with 3. Small cracks appearing at the ends of boards due to rapid drying. Checks are indeed cracks formed by drying stresses, especially at the ends.
- S. Knots are matched with 1. Caused by wood limbs encased by wood of the free trunk. This describes the origin of knots from tree branches.
Final Matching Result
The established correct pairings are:
| P | Q | R | S |
| 4 | 2 | 3 | 1 |
This set of matches corresponds to Option B.
Important Questions from Timber
Which of the following is the main advantage of the plywood?
The hardwood is produced by which of the following trees?
Timber can be made reasonably fire-resistant by
As per Indian Standard (IS 287 : 1993), India is divided into how many zones based on its relative humidity for air seasoning of timber?
Which of the following is an example of endogenous tree?
