Micromeritics & Powder Rheology | Physical Pharmacy | GPAT Mock Test

About this Quiz

Welcome, GPAT aspirants! This mock test is expertly designed to challenge your understanding of Micromeritics and Powder Rheology, a critical topic in Physical Pharmacy. Covering 25 multiple-choice questions, this quiz assesses your knowledge on particle size determination, surface area calculation, and derived powder properties like porosity, density, and flowability. Each question is crafted to mirror the GPAT exam pattern, helping you build confidence and identify areas for improvement. After submitting your answers, you will receive your score instantly with a detailed review of correct and incorrect responses. You can also download a PDF of all questions and their correct answers for offline revision. Good luck!

1. Which of the following diameters is defined as the diameter of a sphere having the same surface area as the particle?

Martin’s diameter Feret’s diameter Projected diameter Stokes’ diameter

2. The Andreasen pipette works on the principle of:

Sieving Sedimentation Adsorption Microscopy

3. A powder with an angle of repose greater than 50 degrees is considered to have:

Excellent flow Good flow Passable flow Very poor flow

4. The BET (Brunauer-Emmett-Teller) equation is primarily used to determine:

Particle size Porosity Specific surface area Bulk density

5. Which density measurement excludes inter-particle voids but includes intra-particle pores?

True density Granule density Bulk density Tapped density

6. The Kozeny-Carman equation is used in which method of surface area determination?

Adsorption method Air permeability method Optical microscopy Sedimentation method

7. A Hausner’s ratio of 1.15 indicates what type of powder flow?

Excellent Good Fair Poor

8. The number of particles per unit weight (N) can be calculated using the formula involving volume-surface mean diameter (dvs) and true density (ρ). What is the correct formula?

N = 6 / (π * dvs³ * ρ) N = 1 / (π * dvs³ * ρ) N = 6 * π / (dvs³ * ρ) N = dvs³ * ρ / 6

9. For spherical particles, the porosity of a powder in its loosest possible packing (cubic arrangement) is approximately:

26% 48% 52% 74%

10. The sieving method is most suitable for determining the particle size of powders in which range?

0.01 to 1 μm 0.5 to 50 μm 50 to 1500 μm Greater than 2000 μm

11. Bulkiness of a powder is the reciprocal of:

True density Bulk density Granule density Porosity

12. In a normal distribution curve for particle size, the mean, median, and mode are:

All different All identical Skewed to the left Skewed to the right

13. The Hatch-Choate equations are used to convert:

Particle size to surface area One type of average particle diameter to another Bulk density to true density Angle of repose to Carr’s index

14. Which method of particle size analysis can provide a 3D representation and information about particle shape?

Sieving Light scattering Optical microscopy Sedimentation

15. The term ‘porosity’ or ‘voids’ (ε) is expressed by which of the following equations?

ε = (Bulk volume – True volume) / Bulk volume ε = Bulk volume / True volume ε = (True volume – Bulk volume) / True volume ε = True volume / Bulk volume

16. A log-normal distribution is often used for particle size data because:

It is simpler to calculate than a normal distribution. It converts a skewed distribution into a symmetric one. It only works for spherical particles. It is mandated by the USP for all powders.

17. Which of the following is a significant limitation of the optical microscopy method for particle size analysis?

It cannot be used for particles smaller than 100 μm. The diameter is obtained from only a two-dimensional image. It is an extremely fast and automated process. It requires the use of Stokes’ law.

18. The number average particle size gives more weight to:

Larger particles in the sample. Smaller particles in the sample. Particles of median size. Particles with the largest surface area.

19. In the context of powder packing, a rhombohedral arrangement represents the:

Loosest packing with highest porosity. Closest packing with lowest porosity. A random, unordered arrangement. An arrangement only seen in liquids.

20. Which of the following properties is NOT derived from bulk and tapped density measurements?

Carr’s Index Hausner’s Ratio Angle of Repose Compressibility

21. True density of a porous solid is determined using:

A graduated measuring cylinder Mercury displacement Helium pycnometer Tapping apparatus

22. The weight average particle size gives more weight to:

Smaller particles in the sample. Larger particles in the sample. Particles with a spherical shape. Particles that are most numerous.

23. Stokes’ Law assumes that the particles are:

Irregular, porous, and settling in turbulent flow. Cubic, non-porous, and settling in any flow. Spherical, smooth, and settling in laminar flow. Needle-shaped, rough, and experiencing hindered settling.

24. A Carr’s Index value of 25% indicates that the powder has what kind of flow property?

Excellent Good Fair Poor

25. The diameter measured between two tangents on opposite sides of the particle, parallel to a fixed direction, is known as:

Martin’s diameter Feret’s diameter Projected diameter Stokes’ diameter

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com