Nursing Elites

1. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

2. Which condition can lead to blood clots and stroke?

• A. Aneurysm
• B. Arrhythmia
• C. Asthma
• D. Hypertension

Correct answer: D

Rationale: Hypertension is the correct answer. Hypertension can cause damage to blood vessels, increasing the risk of blood clots forming, which can potentially lead to a stroke. Aneurysm is a localized, abnormal dilation of a blood vessel that can lead to complications but does not directly cause blood clots and strokes. Arrhythmia refers to irregular heart rhythms and is not directly linked to the formation of blood clots. Asthma is a chronic respiratory condition and does not typically lead to blood clots and strokes.

3. In order to verify if a particular drug is responsible for the recovery of individuals with a disorder, what procedure would be most effective in testing its effectiveness?

• A. Ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo.
• B. Ensure that the subjects do not know whether they are given the drug or the placebo, but the investigators are aware of who has received the medication.
• C. Ensure that the investigators do not know whether they are administering the drug or the placebo, but the subjects do know which they are receiving.
• D. Ensure that both the investigators and the subjects have full knowledge of which subjects are getting the drug and which are getting a placebo.

Correct answer: A

Rationale: The most effective procedure in testing whether the drug is responsible for the recovery is to ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo. This method is known as a double-blind study, which helps eliminate biases and ensures that the results are reliable and not influenced by expectations or beliefs. By keeping both the subjects and investigators unaware of who is receiving the drug or placebo, the study can accurately determine the true impact of the drug on recovery. Choice B is incorrect as it only prevents the subjects from knowing which treatment they are receiving, allowing for potential bias from the investigators. Choice C is also incorrect as it allows for potential bias from the subjects. Choice D is incorrect as full knowledge of treatment allocation can introduce bias and affect the study's validity.

4. Which of the following factors would increase the solubility of a gas in a liquid?

• A. Decreasing temperature
• B. Increasing pressure
• C. Decreasing surface area
• D. Increasing particle size

Correct answer: B

Rationale: The correct answer is increasing pressure. According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. Therefore, increasing pressure would force more gas molecules into the liquid, leading to an increase in solubility. Conversely, decreasing temperature, decreasing surface area, and increasing particle size would not directly impact the solubility of a gas in a liquid. Decreasing temperature typically decreases solubility as gases are less soluble at lower temperatures. Decreasing surface area and increasing particle size are related to surface area and not the pressure above the liquid, thus not affecting solubility as pressure does.

5. Positron emission tomography (PET) scans utilize a key property of positrons for medical imaging. What is this property?

• A. High mass
• B. Positive charge
• C. Extreme stability
• D. Identical behavior to electrons

Correct answer: B

Rationale: Positron emission tomography (PET) scans utilize the property of positrons having a positive charge. Positrons are the antimatter counterpart of electrons, having the same mass but opposite charge. When a positron collides with an electron, they annihilate each other, producing gamma rays that can be detected by the PET scanner to create images of the body's internal structures and functions. Choice A is incorrect because positrons have the same mass as electrons. Choice C is incorrect as positrons are not extremely stable due to their tendency to annihilate when they encounter electrons. Choice D is incorrect as positrons exhibit different behavior than electrons due to their opposite charges.

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