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
The moisture content of a well seasoned wood is in the range-
The defect caused due to over-maturity and unventilated storage of the wood during its transit, is called _______.
The drawback of electric seasoning of timber is
The defect in timber due to broken branch of the tree during the tree growth is:
The best possible wood for sleepers is:
