Nursing Elites

1. What property of a wave remains unchanged when it passes from one medium to another with the same speed?

• A. Frequency
• B. Wavelength
• C. Amplitude
• D. Speed

Correct answer: A

Rationale: When a wave passes from one medium to another with the same speed, its frequency remains unchanged. Frequency is a characteristic of the source of the wave and does not depend on the medium through which the wave is traveling. Wavelength and speed of the wave can change when passing from one medium to another, but frequency remains constant. This is because the frequency of a wave is determined by the source that produces it, and as long as the speed remains constant, the frequency will not be altered. Amplitude, on the other hand, can change based on factors like energy loss or gain, but it is not a property that remains constant when a wave moves between different mediums with the same speed. Speed, although important for the wave's propagation, is not the property that remains unchanged when the wave transitions between mediums with the same speed. Therefore, the correct answer is frequency.

2. The acceleration of a falling object due to gravity has been proven to be 9.8 m/s². A scientist drops a cactus four times and measures the acceleration with an accelerometer and gets the following results: 9.79 m/s², 9.81 m/s², 9.80 m/s², and 9.78 m/s². Which of the following accurately describes the measurements?

• A. They're both accurate and precise.
• B. They're accurate but not precise.
• C. They're precise but not accurate.
• D. They're neither accurate nor precise.

Correct answer: A

Rationale: The measurements are both close to the actual value (accurate) and consistent with each other (precise). Accuracy refers to how close a measurement is to the true value, and precision refers to the reproducibility or consistency of the measurements. In this case, the measured values are all very close to the actual value of 9.8 m/s², indicating accuracy. Additionally, the measurements are clustered closely together, demonstrating precision. Therefore, the measurements are both accurate and precise, making choice A the correct answer. Choices B, C, and D are incorrect because the measurements exhibit both accuracy and precision, as they are close to the true value and also consistent with each other.

3. Which functional group is commonly found in ketones?

• A. Hydroxyl
• B. Carbonyl
• C. Ester
• D. Amine

Correct answer: B

Rationale: Ketones contain a carbonyl functional group, which consists of a carbon atom double-bonded to an oxygen atom. This distinguishes ketones from other functional groups such as hydroxyl, ester, and amine. The presence of the carbonyl group, not hydroxyl (choice A), ester (choice C), or amine (choice D), is characteristic of ketones, making choice B, 'Carbonyl', the correct answer.

4. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

5. Which valve prevents the backflow of blood into the left ventricle as it leaves through the aorta?

• A. Pulmonary semilunar valve
• B. Aortic semilunar valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: B

Rationale: The aortic semilunar valve is the correct answer as it prevents the backflow of blood into the left ventricle once it has been pumped into the aorta. The pulmonary semilunar valve prevents backflow into the right ventricle, the tricuspid valve controls blood flow between the right atrium and ventricle, and the mitral valve regulates blood flow between the left atrium and ventricle. Therefore, option B is the correct choice for this question.

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