This set of Pulp and Paper Multiple Choice Questions and Answers (MCQs) focuses on “Wood and Fibre Physics”.
1. The equilibrium moisture content of wood or wood pulp depends on the temperature and relative humidity of the atmosphere surrounding the specimen.
Explanation: Wood and paper are hygroscopic materials, when fully dried they absorb water vapor from the atmosphere. The equilibrium moisture content of wood or wood pulp depends on the temperature and atmosphere’s humidity surrounding the specimen.
2. What is the full form of FSP?
a) Fiber suction point
b) Fiber soft point
c) Fiber saturation parcel
d) Fiber saturation point
Explanation: The fiber saturation point represents the moisture content of the ligno cellulose material such that additionally adsorbed water is not chemically absorbed to the wood.
3. Wood shrinks and swells as a function of ____________
b) Shear stress
d) Moisture content
Explanation: It is due to the function of moisture content. Above the fiber saturation point there will be no change in wood dimensions according to the moisture content.
4. At low humidities the equilibrium moisture content will be lower.
Explanation: At low humidities the equilibrium moisture content will be lower. Chemically absorbed water requires additional energy to remove it from wood beyond the water’s heat of vaporization.
5. What increases the strength of the paper?
Explanation: The fibers of paper are held together by hydrogen bonding of the hydroxyl groups of cellulose and hemicellulose.
6. What decreases the strength of the paper?
Explanation: Lignin is not able to form H bonds, and results in decrement in strength of paper.
7. What could increase the fiber surface area?
a) Decrease inter-fiber bonding
b) Increase inter-fiber bonding
c) Decrease intra-fiber bonding
d) Increase inter-fiber bonding
Explanation: Factor which increment in fiber surface area is by increasing inter-fiber bonding.
8. Wood taken at room temperature and 99% relative humidity will have how much moisture content approaching?
Explanation: This occurs at about 30% MC (OD) (at room temperature) in wood.
9. Uneven grain orientation may cause severe warping or __ of lumber and furniture is prone to shrinkage as the wood dries.
Explanation: Uneven grain orientation may cause warping or fracturing of lumber and the furniture due to tremendous stresses that could develop from uneven shrinkage as wood dries.
10. __________ bonding holds ligo cellulose fibers together in paper.
Explanation: The strength of R-OH—R-OH hydrogen bonding is 3 – 4kcal/mol. This is relatively as compared to covalent bonds.
Sanfoundry Global Education & Learning Series – Pulp and Paper.
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