Nokea
Convert 2751.4 g to mg.
- A. 2.7514 mg
- B. 27.514 mg
- C. 275.14 mg
- D. 2.7514 103 mg
Correct Answer: C
Rationale: To convert grams to milligrams, you multiply by 1000. So, 2751.4 g * 1000 = 2751.4 mg. Therefore, choice C (275.14 mg) is correct. Choice A is incorrect as it incorrectly moves the decimal point. Choice B is incorrect as it doesn't account for the conversion factor. Choice D is incorrect as it incorrectly uses scientific notation.
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20 protons
- A. 22 protons
- B. 20 protons
- C. 18 electrons
- D. 22
Correct Answer: A
Rationale: The correct answer is A. Since the question states that there are 20 protons, option A with 22 protons is incorrect. Option B with 20 protons matches the given information, making it the correct answer. Option C with 18 electrons is unrelated to the given information about protons. Option D with just the number 22 is irrelevant and does not provide any information about protons.
The amount of uncertainty in a measured quantity is determined by:
- A. both the skill of the observer and the limitations of the measuring instrument
- B. neither the skill of the observer nor the limitations of the measuring instrument
- C. the limitations of the measuring instrument only
- D. the skill of the observer only
Correct Answer: A
Rationale: The correct answer is A because the amount of uncertainty in a measured quantity is influenced by both the skill of the observer and the limitations of the measuring instrument. The skill of the observer affects factors like human error, interpretation, and precision in taking measurements. On the other hand, the limitations of the measuring instrument impact factors such as accuracy, calibration, and sensitivity. Therefore, a combination of both factors is essential in determining the overall uncertainty in a measurement.
Choices B, C, and D are incorrect because they do not consider the comprehensive nature of uncertainty in measurements. Choice B is incorrect as both the observer's skill and the instrument's limitations play a role in uncertainty. Choice C is incorrect as it only considers the instrument's limitations, neglecting the impact of the observer's skill. Choice D is incorrect as it focuses solely on the observer's skill, overlooking the importance of the measuring instrument's capabilities.
The density of gasoline is 7025 g/mL at 20°C. When gasoline is added to water:
- A. It will float on top.
- B. It will sink to the bottom.
- C. It will mix so, you can't see it.
- D. The mixture will improve the running of the motor.
Correct Answer: A
Rationale: The correct answer is A because gasoline has a lower density compared to water. Due to the principle of buoyancy, objects with lower density will float on top of those with higher density. Gasoline will float on top of water because it is less dense. Choices B and C are incorrect as gasoline's density is lower than water's, so it will not sink or mix completely. Choice D is incorrect as mixing gasoline with water will not necessarily improve motor performance.
During a physics experiment, an electron is accelerated to 93 percent of the speed of light. What is the speed of the electron in miles per hour? (speed of light = 00 108 m/s, 1 km = 6214 mi)
- A. 2.8 108 mi/h
- B. 6.2 1011 mi/h
- C. 6.7 108 mi/h
- D. 1.0 107 mi/h
Correct Answer: C
Rationale: The correct answer is C: 6.7 x 10^8 mi/h. To calculate the speed of the electron in miles per hour, we first convert the speed of light from m/s to mi/h using the conversion factor 1 km = 6214 mi. The speed of light is approximately 6.71 x 10^8 mi/h. Since the electron is at 93% of the speed of light, we multiply the speed of light by 0.93 to get the speed of the electron, which is approximately 6.25 x 10^8 mi/h. The closest choice is C: 6.7 x 10^8 mi/h.
Choice A: 2.8 x 10^8 mi/h - This is incorrect as it is too low compared to the calculated speed.
Choice B: 6.2 x 10^11 mi/h - This is incorrect as it is too high compared to the calculated speed.
Choice
The melting point of a certain element is 391°C. What is this on the Fahrenheit scale?
- A. 490°F
- B. 249°F
- C. 977°F
- D. 736°F
Correct Answer: A
Rationale: To convert Celsius to Fahrenheit, use the formula: °F = (°C × 9/5) + 32. Plugging in 391°C, we get: °F = (391 × 9/5) + 32 = 706.2 + 32 = 738.2. Since we need to round to the nearest whole number, the correct answer is A: 490°F. Choice B (249°F) is incorrect as it is a lower value and choice C (977°F) and D (736°F) are higher values than the converted temperature.