How many centimeters are in 1 inch?

Correct Answer: A

Rationale: The correct answer is A: 2.54 cm. One inch is equivalent to 2.54 centimeters. This conversion factor is commonly used when converting measurements between the metric and imperial systems. Choice B (3 cm) is incorrect as it is not the accurate conversion factor for 1 inch. Choice C (2 cm) is also incorrect as it does not reflect the correct conversion. Choice D (1 cm) is incorrect as it inaccurately states the conversion value for 1 inch.

Correct Answer: A

Rationale: To convert milligrams (mg) to micrograms (mcg), you need to multiply by 1000 because there are 1000 micrograms in 1 milligram. Therefore, 0.2 mg * 1000 = 200 mcg. This is the correct conversion. Choice B (20 mcg) is incorrect because it does not account for multiplying by 1000. Choice C (2000 mcg) is incorrect as it mistakenly multiplies by 10 instead of 1000. Choice D (2 mcg) is incorrect as it does not involve any conversion from milligrams to micrograms.

Correct Answer: A

Rationale: To convert liters to milliliters, you need to multiply by 1000 since 1 liter is equal to 1000 milliliters. Therefore, 0.5 liters multiplied by 1000 equals 500 milliliters. Choice A, 500 mL, is the correct answer. Choice B, 50 mL, is incorrect as it represents converting 0.05 liters to milliliters. Choice C, 5 mL, is incorrect as it represents converting 0.005 liters to milliliters. Choice D, 0.5 mL, is incorrect as it represents the original amount in milliliters, not the conversion of liters to milliliters.

Correct Answer: B

Rationale: To convert millimeters to centimeters, you need to divide by 10 since there are 10 millimeters in 1 centimeter. Therefore, 345,000 mm · 10 = 34,500 cm. Choice A is incorrect because it is a factor of 10 higher than the correct answer. Choice C is incorrect because it represents the original quantity in centimeters, not the converted value. Choice D is incorrect as it erroneously multiplies the millimeters by 1,000 instead of dividing by 10 to convert to centimeters.

Correct Answer: A

Rationale: The prefix 'kilo-' in the metric system signifies a factor of 1000, which is equivalent to 10^3. Therefore, when using the prefix 'kilo-', it implies multiplying the base unit by 1000. For instance, one kilometer is equal to 1000 meters. Choices B, C, and D are incorrect as they do not accurately represent the factor associated with the prefix 'kilo-'.

Correct Answer: A

Rationale: To convert grams to milligrams, you need to multiply by 1000, not 10000. Therefore, to convert 0.04 grams to milligrams, you multiply 0.04 by 1000, which equals 40 mg. Choice A (40 mg) is the correct answer. Choice B (4 mg) is incorrect as it represents converting 0.004 grams to milligrams. Choice C (400 mg) is incorrect as it is 10 times the correct conversion. Choice D (0.4 mg) is incorrect as it is 10 times smaller than the correct conversion.

Correct Answer: B

Rationale: To convert 0.2 liters to milliliters, you need to multiply by 1,000 because there are 1,000 milliliters in a liter. So, 0.2 * 1,000 = 200 milliliters. Therefore, the correct answer is 200 ml. Choice A (20 ml) is incorrect because it represents 0.02 liters, not 0.2 liters. Choice C (2 ml) is incorrect as it represents 0.002 liters. Choice D (2000 ml) is incorrect as it represents 2 liters, not 0.2 liters.

Correct Answer: C

Rationale: The correct answer is 1,000 milliliters in 1 liter. The conversion from liters to milliliters involves multiplying by 1,000 since 1 liter is equivalent to 1,000 milliliters. Choice A, 10 mL, is incorrect as it represents only a fraction of a liter. Choice B, 100 mL, is also incorrect as it is one-tenth of a liter. Choice D, 10,000 mL, is significantly larger than the correct answer and represents 10 liters, not 1 liter.

Correct Answer: A

Rationale: The correct answer is A: 298.15 K. The conversion from Celsius to Kelvin is K = C + 273.15. Therefore, 25°C is equivalent to 298.15 K, as 25 + 273.15 = 298.15. Choice B, 273.15 K, is the freezing point of water in Kelvin, not the equivalent of 25°C. Choice C, 250 K, and Choice D, 25 K, are incorrect conversions and do not align with the correct formula for converting Celsius to Kelvin.