How many centimeters are in 1 meter?

Correct Answer: B

Rationale: The correct answer is B: 100 cm. 1 meter is equivalent to 100 centimeters. Choice A (10 cm) is incorrect as it represents the conversion of decimeters to centimeters. Choice C (1,000 cm) is incorrect as it represents the conversion of meters to millimeters. Choice D (10,000 cm) is incorrect as it represents the conversion of meters to centimeters with an extra zero.

Correct Answer: A

Rationale: To convert grams to kilograms, divide by 1,000 since there are 1,000 grams in a kilogram. Therefore, 34.5 grams · 1,000 = 0.0345 kilograms. The correct answer is 3.45 kg (not 3.45 grams, which is the amount given in the initial question). Choices B and C are incorrect as they do not involve the conversion from grams to kilograms. Choice D is also incorrect as it presents the value in grams instead of kilograms.

Correct Answer: A

Rationale: To convert liters to milliliters, you multiply the number of liters by 1000. Therefore, 0.5 liters equals 500 milliliters. This conversion is standard in various fields, making choice A the correct answer. Choices B, C, and D are incorrect because they do not correctly convert liters to milliliters.

Correct Answer: A

Rationale: To convert milligrams to micrograms, you need to multiply by 1000 because there are 1000 micrograms in a milligram. Therefore, 0.025 mg x 1000 = 25 mcg. This means that the correct answer is A, 25 mcg. Choice B, 250 mcg, is incorrect because it incorrectly multiplies by 10 instead of 1000. Choice C, 2.5 mcg, is incorrect as it inaccurately divides the value by 10. Choice D, 0.25 mcg, is also incorrect as it divides the value by 100 instead of multiplying by 1000.

Correct Answer: B

Rationale: The correct answer is B: 2.54 cm. One inch is equivalent to 2.54 centimeters in the metric system. This conversion factor is commonly used in converting measurements between the imperial and metric systems. Choice A (1.54 cm), Choice C (3.54 cm), and Choice D (4.54 cm) are incorrect conversions and do not represent the accurate metric equivalent of 1 inch.

Correct Answer: D

Rationale: To convert milligrams to micrograms, you need to multiply by 1000 since there are 1000 micrograms in a milligram. Therefore, to convert 0.075 mg to mcg, you would multiply 0.075 by 1000, which equals 75. Thus, the correct conversion is 750 mcg. Choice A, 75 mcg, is incorrect as it's the result if you mistakenly multiply by 10 instead of 1000. Choice B, 7.5 mcg, is incorrect as it's the result if you divide by 10 instead of multiplying by 1000. Choice C, 0.75 mcg, is incorrect as it's the result if you divide by 100 instead of multiplying by 1000.

Correct Answer: C

Rationale: The prefix 'femto-' stands for 10^-15, making femtometer equal to 10^-15 meters. The incorrect choices are A and B because 'pico-' represents 10^-12 (picometer) and 'nano-' represents 10^-9 (nanometer), respectively. Choice D is also incorrect as 'pico-' is associated with 10^-12, not 10^-15.

Correct Answer: B

Rationale: To convert kilometers to meters, you need to multiply by 1,000 since there are 1,000 meters in a kilometer. Therefore, 345 km multiplied by 1,000 equals 345,000 meters. Choice A is incorrect as it incorrectly places the comma. Choice C is incorrect as it adds an extra zero at the end. Choice D is incorrect as it adds an extra zero at the beginning, resulting in an incorrect conversion.

Correct Answer: A

Rationale: To convert 0.04 grams to milligrams, you need to multiply by 1000, not 10000. Therefore, 0.04 grams equals 40 milligrams (0.04g * 1000 = 40mg). Choice B, '4 mg,' is incorrect as it reflects the value as if it was in grams. Choice C, '400 mg,' is incorrect as it incorrectly multiplies by 100 instead of 1000. Choice D, '0.4 mg,' is incorrect as it incorrectly moves the decimal point to the right instead of multiplying by 1000.