Plywoods are classified as Boiling Water Resistant (BWR) grade and Moisture Resistant (MR) grade depending on
- Aappearance of surface
- Bthickness of plywood
- Cdensity of plywood
- Dbond strength developed by adhesive used for bonding the veneersCorrect
Solution
Concept
Classification of plywood (IS 303)
Step-by-step solution
1. The type of adhesive decides water resistance. 2. MR grade: urea-formaldehyde glue; BWR grade: phenol-formaldehyde glue (better bond under boiling water).
Explanation
BWR and MR grades are classified by the water resistance of the bond between veneers, which depends on the adhesive used.
Why the other options are wrong
Surface appearance, thickness and density do not define BWR/MR classes.
Shortcut
MR = urea glue; BWR = phenolic glue; marine = best.
Common mistake
Choosing surface appearance.
Correct answer: D) bond strength developed by adhesive used for bonding the veneers