Understanding weights and measures is essential for B. Pharm students because precise units and conversions underpin safe pharmaceutical practice. This guide contrasts the Imperial system and the Metric system, detailing key units of mass, volume, and length (kilogram, gram, liter, pound, ounce, inch), common conversion factors, and implications for dosage calculations, compounding, and labeling. Emphasis is placed on unit prefixes, density-based mass–volume conversions, and regulatory expectations for accurate measurement. Mastery of these concepts strengthens pharmacy calculations, reduces dosing errors, and supports quality assurance in formulation and dispensing. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which measurement system uses the kilogram as the primary unit of mass?
- Imperial system
- Metric system
- Apothecary system
- Troy system
Correct Answer: Metric system
Q2. How many centimetres are there in one inch?
- 1.00 cm
- 2.54 cm
- 3.14 cm
- 0.393 cm
Correct Answer: 2.54 cm
Q3. Approximately how many kilograms are in one avoirdupois pound?
- 0.3048 kg
- 0.9072 kg
- 0.4536 kg
- 2.2046 kg
Correct Answer: 0.4536 kg
Q4. One US fluid ounce is approximately how many millilitres?
- 15.00 mL
- 29.57 mL
- 28.41 mL
- 10.00 mL
Correct Answer: 29.57 mL
Q5. One US gallon equals approximately how many liters?
- 1.609 L
- 4.546 L
- 3.785 L
- 0.946 L
Correct Answer: 3.785 L
Q6. In pharmacy practice, one grain is commonly taken as approximately how many milligrams?
- 100 mg
- 64.8 mg
- 15.43 mg
- 250 mg
Correct Answer: 64.8 mg
Q7. Which prefix denotes a factor of 10^3 in the metric system?
- centi-
- milli-
- kilo-
- micro-
Correct Answer: kilo-
Q8. How many avoirdupois ounces are in one avoirdupois pound?
- 8 ounces
- 12 ounces
- 16 ounces
- 20 ounces
Correct Answer: 16 ounces
Q9. Approximately how many US pints are contained in 500 mL?
- 0.5 pint
- 1.0 pint
- 1.06 pints
- 2.11 pints
Correct Answer: 1.06 pints
Q10. What is the correct formula to convert Celsius to Fahrenheit?
- °F = (°C − 32) × 5/9
- °F = (°C × 9/5) + 32
- °F = (°C × 5/9) − 32
- °F = (°C + 273.15) × 9/5
Correct Answer: °F = (°C × 9/5) + 32
Q11. Density is best defined as which of the following?
- Volume per unit mass
- Mass per unit volume
- Mass per unit area
- Weight per unit length
Correct Answer: Mass per unit volume
Q12. If a liquid has a density of 1.2 g/mL, what is the mass of 100 mL of this liquid?
- 83.3 g
- 120 g
- 100 g
- 12 g
Correct Answer: 120 g
Q13. A 5% w/v solution contains how many grams of solute per 100 mL?
- 0.5 g per 100 mL
- 5 g per 100 mL
- 50 g per 100 mL
- 0.05 g per 100 mL
Correct Answer: 5 g per 100 mL
Q14. Convert 250 mg into grains (1 grain ≈ 64.8 mg). Approximately how many grains is this?
- 1.6 grains
- 3.9 grains
- 6.2 grains
- 0.4 grains
Correct Answer: 3.9 grains
Q15. One mile equals approximately how many meters?
- 1000 m
- 1609.34 m
- 5280 m
- 2000 m
Correct Answer: 1609.34 m
Q16. A US fluid dram is approximately how many millilitres?
- 1.23 mL
- 3.696 mL
- 10.00 mL
- 0.378 mL
Correct Answer: 3.696 mL
Q17. What is the SI base unit for length?
- Centimetre
- Inch
- Foot
- Meter
Correct Answer: Meter
Q18. Which metric prefix represents 10^-3?
- micro-
- milli-
- centi-
- deci-
Correct Answer: milli-
Q19. Convert 0.75 L to millilitres.
- 7.5 mL
- 75 mL
- 750 mL
- 7500 mL
Correct Answer: 750 mL
Q20. How many grams are there in 2 kilograms?
- 200 g
- 2000 g
- 20 g
- 0.2 g
Correct Answer: 2000 g
Q21. A tablet contains 250 mg of active drug. How many tablets provide a 0.5 g dose?
- 1 tablet
- 2 tablets
- 3 tablets
- 4 tablets
Correct Answer: 2 tablets
Q22. Approximately how many grams does 250 mL of water weigh at normal laboratory conditions (assume density ≈1 g/mL)?
- 25 g
- 250 g
- 1000 g
- 0.25 g
Correct Answer: 250 g
Q23. In US household measures, how many teaspoons are in one tablespoon?
- 2 teaspoons
- 3 teaspoons
- 4 teaspoons
- 5 teaspoons
Correct Answer: 3 teaspoons
Q24. Which is larger: one US fluid ounce or one Imperial (UK) fluid ounce?
- One Imperial fluid ounce is larger
- They are exactly equal
- One US fluid ounce is larger
- Depends on temperature
Correct Answer: One US fluid ounce is larger
Q25. How many milligrams equal 1000 micrograms (mcg)?
- 0.1 mg
- 1 mg
- 10 mg
- 100 mg
Correct Answer: 1 mg
Q26. The defined conversion 1 inch = 2.54 cm is considered to have how many significant figures?
- Two significant figures
- Three significant figures
- It is an exact defined value (effectively infinite significant figures)
- One significant figure
Correct Answer: It is an exact defined value (effectively infinite significant figures)
Q27. Approximately how many pounds are there in one kilogram?
- 0.454 lb
- 1.0 lb
- 2.205 lb
- 10.00 lb
Correct Answer: 2.205 lb
Q28. Convert 10 mL to teaspoons (1 teaspoon ≈ 4.93 mL). Approximately how many teaspoons is 10 mL?
- 0.49 teaspoons
- 1.5 teaspoons
- 2.03 teaspoons
- 4.93 teaspoons
Correct Answer: 2.03 teaspoons
Q29. Which unit is most commonly used to express IV infusion rate in hospitals?
- mL/hr
- g/mL
- mg/kg
- drops per second
Correct Answer: mL/hr
Q30. A 1:1000 w/v solution corresponds to which concentration in mg per mL?
- 0.1 mg/mL
- 1 mg/mL
- 10 mg/mL
- 100 mg/mL
Correct Answer: 1 mg/mL
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