What is the base unit for mass in the metric system?
- A. milligrams
- B. grams
- C. kilograms
- D. tons
Correct Answer: B
Rationale: The base unit for mass in the metric system is grams. Grams are the fundamental unit of mass in the metric system, representing smaller quantities than kilograms and tons. Milligrams are a smaller unit of mass, kilograms are a larger unit, and tons are even larger units. Therefore, the correct choice is grams.
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What is 0.03 as a fraction?
- A. 3/100
- B. 1/30
- C. 1/3
- D. 1/10
Correct Answer: A
Rationale: To convert a decimal to a fraction, you place the decimal value over a power of 10, where the number of zeros in the denominator is equal to the number of decimal places in the decimal. In this case, 0.03 can be written as 3/100 because there are two decimal places (hundredths). This fraction is already in simplest form. Choice B, 1/30, is incorrect as it represents 0.033 as a fraction. Choice C, 1/3, is incorrect as it represents 0.3 as a fraction. Choice D, 1/10, is incorrect as it represents 0.1 as a fraction.
How many micrograms (mcg) are equivalent to 0.5 milligrams (mg)?
- A. 500 mcg
- B. 50 mcg
- C. 5 mcg
- D. 0.5 mcg
Correct Answer: A
Rationale: To convert milligrams to micrograms, you need to multiply by 1000 because there are 1000 micrograms in 1 milligram. Therefore, 0.5 mg x 1000 = 500 mcg. This conversion is crucial in medication dosage calculations to ensure precise administration. Choice B, 50 mcg, is incorrect as it represents 0.05 mg. Choice C, 5 mcg, is incorrect as it corresponds to 0.005 mg. Choice D, 0.5 mcg, is incorrect because it is the same value as the initial amount in milligrams, rather than the converted value to micrograms.
The SI prefixes micro and milli represent, respectively:
- A. 10^-6 and 10^-3
- B. 10^-9 and 10^-6
- C. 10^-12 and 10^-9
- D. 10^-15 and 10^-12
Correct Answer: A
Rationale: The prefixes 'micro-' and 'milli-' represent 10^-6 and 10^-3, respectively. 'Micro-' denotes one-millionth (10^-6), while 'milli-' denotes one-thousandth (10^-3). Choice B is incorrect because it confuses the order of magnitudes for micro and milli. Choice C and D are also incorrect as they provide the wrong values for the prefixes micro and milli.
What is the equivalent of 35.4 centimeters in kilometers (km)?
- A. 0.00354 km
- B. 0.000354 km
- C. 0.00345 km
- D. 0.0345 km
Correct Answer: B
Rationale: To convert centimeters to kilometers, you need to divide by 100,000 since there are 100,000 centimeters in a kilometer. Therefore, 35.4 cm · 100,000 = 0.000354 km. Choice A (0.00354 km) is incorrect as it represents dividing by 10,000, not 100,000. Choice C (0.00345 km) is incorrect as the last digit is different from the correct answer. Choice D (0.0345 km) is incorrect as it represents dividing by 1,000, not by 100,000.
What is 0.025 mg converted to micrograms?
- A. 25 mcg
- B. 250 mcg
- C. 2.5 mcg
- D. 0.25 mcg
Correct Answer: A
Rationale: To convert milligrams to micrograms, you need to multiply by 1000, not 10000. Therefore, 0.025 mg is equal to 25 mcg. The correct conversion is obtained by recognizing that 1 milligram (mg) is equal to 1000 micrograms (mcg). Choices B, C, and D are incorrect because they do not correctly convert milligrams to micrograms. Choice B is 10 times the correct answer, choice C is 100 times less, and choice D is 100 times less than the correct conversion.