Timber MCQ with answer and solution

Concept

IS 3129-1985 covers low density particle boards. It gives allowed tolerances for the length, width and thickness of finished boards.

Step-by-step solution

1. IS 3129-1985 is the code for low density particle boards made from wood or other lignocellulosic material. 2. The code gives dimensional tolerances for finished boards. 3. The tolerance commonly quoted for length (and width) of finished boards is ±8 mm.

Explanation

Particle boards are cut to standard sizes, but small changes in size are allowed. For low density particle boards under IS 3129-1985, the commonly quoted length tolerance is ±6 mm. Thickness has a much smaller tolerance than length.

Why the other options are wrong

B (±4 mm): not the value usually quoted for length in IS 3129. C (±2 mm): too strict for board length; small values like this apply to thickness, not length.

Shortcut

Low density particle board (IS 3129): length tolerance ±8 mm.

Common mistake

Mixing up the length tolerance with the much smaller thickness tolerance, or with values from other board codes such as IS 3087.