Sieve shaker – principle, construction, working, uses, merits, demerits MCQs With Answer

Introduction: The sieve shaker is an essential laboratory instrument for B.Pharm students to understand particle size analysis. Covering the principle of sieving, detailed construction of sieve stacks, and the working parameters such as amplitude, frequency and sieving time, this guide explains common uses in granule sizing, powder classification and quality control. You will also learn merits like speed and reproducibility, and demerits including mesh blinding and limitations with cohesive powders. Practical aspects such as wet vs. dry sieving, sample preparation, calibration and troubleshooting are included to build competency for pharmaceutical formulation and QC labs. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the fundamental principle behind a sieve shaker?

• Separation by magnetic susceptibility
• Size-based separation using mesh apertures
• Centrifugal separation of densities
• Separation by chemical affinity

Correct Answer: Size-based separation using mesh apertures

Q2. Which component is NOT part of a typical sieve shaker construction?

• Vibratory drive
• Sieve stack and clamp
• Vacuum pump
• Timer control

Correct Answer: Vacuum pump

Q3. In sieve shaker operation, increasing sieve amplitude primarily affects:

• The chemical composition of the sample
• The rate of particle passage through apertures
• Mesh aperture size
• Electrical conductivity of particles

Correct Answer: The rate of particle passage through apertures

Q4. For accurate particle size distribution, sieves are usually stacked with:

• Finest mesh at top and coarsest at bottom
• Random order of mesh sizes
• Coarsest mesh at top and finest at bottom
• All sieves of same mesh interleaved

Correct Answer: Coarsest mesh at top and finest at bottom

Q5. Which material is most commonly used for sieve frames in pharmaceutical labs?

• Brass
• Stainless steel
• Wood
• Polyvinyl chloride

Correct Answer: Stainless steel

Q6. Wet sieving is preferred over dry sieving when:

• Particles are highly friable
• Powders are hydrophobic
• Particles form agglomerates due to moisture or electrostatics
• Sample is extremely coarse

Correct Answer: Particles form agglomerates due to moisture or electrostatics

Q7. Which parameter should be controlled to avoid mesh blinding?

• Sample color
• Sieving time and amplitude
• Ambient light
• Magnetic field strength

Correct Answer: Sieving time and amplitude

Q8. The term “cumulative percent retained” refers to:

• Percent of material retained on a specific sieve only
• Percent of material passing the finest sieve
• Running total percentage of sample retained from top to a given sieve
• Percentage lost during weighing

Correct Answer: Running total percentage of sample retained from top to a given sieve

Q9. Which international standard often guides sieve analysis in pharmaceuticals?

• ASTM and ISO standards
• FDA color charts
• EPA water guidelines
• WHO refrigeration standards

Correct Answer: ASTM and ISO standards

Q10. A sieve shaker with electromagnetic drive typically provides:

• Rotational motion only
• Controlled linear or circular vibration at set frequency
• Hydraulic compression
• Acoustic resonance separation

Correct Answer: Controlled linear or circular vibration at set frequency

Q11. The mesh aperture size is usually defined in:

• Millimeters or micrometers
• Grams
• Seconds
• Degrees Celsius

Correct Answer: Millimeters or micrometers

Q12. Which factor does NOT significantly affect sieve analysis results?

• Sample moisture content
• Sieve aperture accuracy
• Operator technique
• Ambient atmospheric pressure at sea level

Correct Answer: Ambient atmospheric pressure at sea level

Q13. The purpose of a cover on the top sieve is to:

• Increase vibration amplitude
• Prevent loss of fines and avoid contamination
• Change mesh aperture size
• Provide sampling for chemical assays

Correct Answer: Prevent loss of fines and avoid contamination

Q14. Which of the following is a common merit of using a sieve shaker?

• Requires large sample size only
• Provides rapid and reproducible particle size distribution
• Eliminates need for calibration
• Works equally for liquids and gases

Correct Answer: Provides rapid and reproducible particle size distribution

Q15. A demerit of sieve analysis is:

• High resolution for nanoparticles
• Susceptibility to mesh blinding and poor for very fine powders
• Universal suitability for all powders
• Automated chemical identification

Correct Answer: Susceptibility to mesh blinding and poor for very fine powders

Q16. For pharmaceutical granules, an appropriate sieving time is typically determined by:

• Manufacturer’s intuition
• Trial runs until mass retained stabilizes
• Color of the granules
• Ambient humidity only

Correct Answer: Trial runs until mass retained stabilizes

Q17. Which test helps ensure sieve apertures meet specifications?

• Mesh calibration using test sieves or calibration certificates
• pH measurement
• Viscosity testing
• Spectrophotometry

Correct Answer: Mesh calibration using test sieves or calibration certificates

Q18. What is “undersize fraction” in sieve analysis?

• Material retained on a sieve
• Material passing through a given sieve aperture
• Material adhering to sieve frame
• Material lost during transfer

Correct Answer: Material passing through a given sieve aperture

Q19. Which maintenance activity prolongs sieve life?

• Heating sieves to extreme temperatures
• Regular brushing, cleaning and proper storage
• Storing in direct sunlight
• Using metal brushes aggressively on mesh

Correct Answer: Regular brushing, cleaning and proper storage

Q20. In sieve nomenclature, a “mesh number” refers to:

• Number of openings per linear inch
• Diameter of sieve frame
• Weight capacity in grams
• Vibration frequency setting

Correct Answer: Number of openings per linear inch

Q21. Which precaution reduces electrostatic adhesion during dry sieving?

• Increase mesh aperture size only
• Use anti-static agents or humidity control
• Use stronger vibration irrespective of sample
• Cool the sample to freezing

Correct Answer: Use anti-static agents or humidity control

Q22. Which type of sieve shaker is best for fragile pharmaceutical granules to avoid breakage?

• High-amplitude impact shaker
• Low-amplitude gentle oscillatory shaker
• Rotary cutter
• Centrifuge-based shaker

Correct Answer: Low-amplitude gentle oscillatory shaker

Q23. Which analytical output is commonly derived from sieve analysis?

• Melting point
• Differential scanning calorimetry curve
• Particle size distribution curve and d10, d50, d90 values
• Mass spectrometry profile

Correct Answer: Particle size distribution curve and d10, d50, d90 values

Q24. Mesh blinding is best described as:

• Permanent enlargement of apertures
• Blockage of mesh openings by particles or fines
• Color change of mesh due to oxidation
• Rupture of sieve frame

Correct Answer: Blockage of mesh openings by particles or fines

Q25. Which action helps prevent mesh blinding during sieving of sticky powders?

• Use of a larger sample size without cleaning
• Applying silicone spray or selecting a finer mesh
• Using anti-blinding agents, wet sieving or ultrasonic sieving
• Heating the mesh to melt particles

Correct Answer: Using anti-blinding agents, wet sieving or ultrasonic sieving

Q26. The mass median diameter (d50) represents:

• The largest particle in the sample
• The diameter below which 50% of the sample mass lies
• The diameter above which 90% of the sample mass lies
• The smallest measurable particle

Correct Answer: The diameter below which 50% of the sample mass lies

Q27. In sieve analysis, which calculation provides percent retained on each sieve?

• Mass retained on sieve divided by total sample mass multiplied by 100
• Mass passing through finest sieve divided by sieve aperture
• Mesh number divided by mass
• Amplitude times frequency

Correct Answer: Mass retained on sieve divided by total sample mass multiplied by 100

Q28. Which is a correct troubleshooting step if results show excessive fines?

• Ignore and report results
• Check for broken granules during sieving and reduce vibration intensity
• Increase sieving time indefinitely
• Change sieve stack order randomly

Correct Answer: Check for broken granules during sieving and reduce vibration intensity

Q29. For particle sizing below 45 µm, sieve analysis is:

• Highly accurate and preferred
• Generally unsuitable; alternative techniques recommended
• Required by USP
• Best done using wooden sieves

Correct Answer: Generally unsuitable; alternative techniques recommended

Q30. Which practice ensures representative sampling prior to sieving?

• Taking only surface material
• Using coning and quartering or riffle sampling to obtain a representative subsample
• Using the entire batch without homogenization
• Sampling only after sieving

Correct Answer: Using coning and quartering or riffle sampling to obtain a representative subsample

Q31. Ultrasonic sieving is helpful because it:

• Reduces need for mesh calibration
• Helps de-agglomerate fine particles and reduce mesh blinding
• Eliminates the need for a sieve stack
• Mixes chemical reagents into powder

Correct Answer: Helps de-agglomerate fine particles and reduce mesh blinding

Q32. Which is a common error when reporting sieve analysis data?

• Reporting cumulative percent passing instead of retained
• Forgetting to state sieving conditions such as time and amplitude
• Using proper significant figures
• Including sieve calibration info

Correct Answer: Forgetting to state sieving conditions such as time and amplitude

Q33. The effect of humidity during sieving can cause:

• Reduced cohesion among particles
• Increased particle agglomeration and mesh blinding
• Instant drying of the sample
• Change in sieve aperture size

Correct Answer: Increased particle agglomeration and mesh blinding

Q34. Which instrument setting is least likely to be adjusted for different samples?

• Vibration frequency
• Sieving time
• Mesh aperture sizes
• Weight of the sieve frame material

Correct Answer: Weight of the sieve frame material

Q35. When interpreting sieve data, a narrow distribution indicates:

• A wide range of particle sizes
• Particles concentrated around a similar size
• High degree of mesh blinding
• Incorrect stacking order

Correct Answer: Particles concentrated around a similar size

Q36. Which safety precaution is important when using a sieve shaker?

• Operate with open sieve stack exposed to hands
• Ensure stack is clamped and machine cover closed during operation
• Disconnect grounding only during use
• Use flammable solvents near electrical shaker

Correct Answer: Ensure stack is clamped and machine cover closed during operation

Q37. Which property of particles does sieve analysis NOT directly measure?

• Particle size
• Particle shape or morphology
• Distribution of sizes
• Percent retained on sieves

Correct Answer: Particle shape or morphology

Q38. The mean mesh aperture of a sieve is validated by:

• Visual inspection only
• Certification from manufacturer or calibration using test wires or certified test sieves
• Weighing of the sieve frame
• Running a chemical assay on the mesh

Correct Answer: Certification from manufacturer or calibration using test wires or certified test sieves

Q39. In pharmaceutical QC, sieve analysis is used to monitor:

• Tablet dissolution only
• Granule size distribution, blend uniformity and consistency of milling processes
• Sterility of parenterals
• pH of suspensions

Correct Answer: Granule size distribution, blend uniformity and consistency of milling processes

Q40. Which sieve cleaning method is recommended to avoid damaging mesh?

• Pressurized metal scraping
• Gentle brushing with soft bristles and ultrasonic cleaning when appropriate
• Using abrasive grinders
• Cutting holes to remove stuck particles

Correct Answer: Gentle brushing with soft bristles and ultrasonic cleaning when appropriate

Q41. To convert mesh number to approximate aperture, you would consult:

• Mesh-to-aperture conversion charts for the specific standard
• Color charts
• Temperature tables
• pH scale

Correct Answer: Mesh-to-aperture conversion charts for the specific standard

Q42. Which sieve type is best for aggressive corrosion-resistant applications?

• Wooden sieves
• Stainless steel woven wire sieves
• Paper sieves
• Iron cast sieves

Correct Answer: Stainless steel woven wire sieves

Q43. If a sample wets and clogs during wet sieving, a good corrective step is to:

• Continue sieving longer
• Adjust detergent concentration or change medium to reduce surface tension
• Heat the sample to evaporation
• Switch to coarser meshes only

Correct Answer: Adjust detergent concentration or change medium to reduce surface tension

Q44. Which metric indicates the spread of particle sizes in a distribution?

• Standard deviation or span (e.g., (d90-d10)/d50)
• Total sample mass only
• Mesh frame color
• Vibration amplitude only

Correct Answer: Standard deviation or span (e.g., (d90-d10)/d50)

Q45. The main limitation of sieve analysis compared to laser diffraction is:

• Sieve analysis is faster for sub-micron particles
• Lower resolution for very fine particles and sensitivity to particle shape
• Sieve analysis measures chemical impurities
• Sieve analysis uses photons for sizing

Correct Answer: Lower resolution for very fine particles and sensitivity to particle shape

Q46. Which sample property could falsely increase the apparent particle size when sieving?

• Perfectly spherical particles
• Agglomeration of primary particles
• Use of appropriately sized sieves
• Dry free-flowing powder

Correct Answer: Agglomeration of primary particles

Q47. For repeatability of sieve results, documentation should include:

• Only the final graph
• Sieving time, amplitude/frequency, sample mass, sieve IDs and calibration status
• Operator name only
• Room décor

Correct Answer: Sieving time, amplitude/frequency, sample mass, sieve IDs and calibration status

Q48. Which modification improves sieving of moist sticky powders?

• Reducing sieve aperture size
• Using wet sieving with appropriate dispersant or ultrasonic assistance
• Increasing sample mass drastically
• Removing the sieve stack during operation

Correct Answer: Using wet sieving with appropriate dispersant or ultrasonic assistance

Q49. A practical step to validate a sieve shaker’s performance is to:

• Compare results with certified test materials and check repeatability
• Run it without sample to produce data
• Change mesh during test randomly
• Operate it in a vacuum

Correct Answer: Compare results with certified test materials and check repeatability

Q50. Which statement best describes the use of sieve analysis in formulation development?

• Sieve analysis is irrelevant to granulation and tableting
• It helps correlate particle size with flow, compaction and dissolution behavior
• It replaces dissolution testing
• It is used only for final product packaging

Correct Answer: It helps correlate particle size with flow, compaction and dissolution behavior

Download