Nursing Elites

1. What is the principle behind optical fibers used in communication?

• A. Reflection of light within the fiber
• B. Refraction of light due to different densities within the fiber
• C. Total internal reflection guiding light through the fiber core
• D. Diffraction of light around bends in the fiber

Correct answer: C

Rationale: Optical fibers used in communication rely on the principle of total internal reflection guiding light through the fiber core. Total internal reflection occurs when light traveling through the core of the fiber is reflected back into the core due to the higher refractive index of the core compared to the cladding. This reflection ensures that the light remains confined within the core and propagates along the fiber without significant loss, allowing for efficient transmission of signals over long distances in optical communication systems. Choice A is incorrect because optical fibers do not primarily rely on simple reflection; instead, they utilize total internal reflection to guide light. Choice B is incorrect as the primary principle is not the refraction of light due to different densities within the fiber, but rather total internal reflection. Choice D is incorrect as diffraction is not the main principle behind optical fibers, which mainly rely on total internal reflection to guide light through the fiber core.

2. Which of the following is listed in order from least to greatest?

• A. -2 3/4, -2 7/8, -1/5, 2/5, 1/8
• B. -1/5, 1/8, 2/5, -2 3/4, -2 7/8
• C. -2 7/8, -2 3/4, -1/5, 1/8, 2/5
• D. 1/8, 2/5, -1/5, -2 7/8, -2 3/4

Correct answer: C

Rationale: To determine the order from least to greatest, we can convert all fractions and mixed numbers to decimals or use a least common denominator. Converting the fractions in Choice C to decimals, we get -2.875, -2.75, -0.2, 0.125, and 0.4 when reading from left to right. Negative integers with larger absolute values are less than negative integers with smaller absolute values. Therefore, the correct answer is Choice C. Choices A, B, and D are incorrect because they do not present the numbers in the correct order from least to greatest when converted to decimals or compared using common denominators.

3. Nuclear fusion powers the sun and other stars. What is the main obstacle to achieving controlled nuclear fusion on Earth for energy production?

• A. Lack of suitable materials to handle high temperatures and pressures.
• B. Limited availability of fusion fuels like deuterium and tritium.
• C. Difficulty in containing the plasma where fusion occurs.
• D. All of the above

Correct answer: D

Rationale: The main obstacle to achieving controlled nuclear fusion on Earth for energy production involves a combination of factors. A) Lack of suitable materials to handle high temperatures and pressures is a significant challenge due to the extreme conditions required for fusion reactions. B) Limited availability of fusion fuels like deuterium and tritium can pose a constraint on the scalability and sustainability of fusion energy. C) Difficulty in containing the plasma where fusion occurs is another critical issue as plasma instabilities and heat losses can hinder the efficiency of fusion reactions. Therefore, all of the options (A, B, and C) contribute to the challenges in achieving controlled nuclear fusion for energy production on Earth.

4. Select the noun that the underlined adjectives describe: 'Two weeks after his surgery, Henry felt strong and healthy.'

• A. weeks
• B. his
• C. surgery
• D. Henry

Correct answer: D

Rationale: The correct answer is D (Henry) because the adjectives 'strong and healthy' describe 'Henry.' In this sentence, 'Henry' is the subject being described as strong and healthy, not 'weeks,' 'his,' or 'surgery.' While 'weeks' and 'surgery' are nouns mentioned in the sentence, they are not the nouns being described by the adjectives in question. 'His' is a possessive pronoun referring to Henry and does not match the criteria of being directly described by the adjectives 'strong and healthy.' Therefore, 'Henry' is the noun that the adjectives specifically describe in this context.

5. What is the purpose of genetic counseling?

• A. To treat genetic disorders.
• B. To diagnose genetic diseases in newborns.
• C. To provide information and support to individuals and families with genetic risks.
• D. To collect DNA samples for research purposes.

Correct answer: C

Rationale: The purpose of genetic counseling is to provide information and support to individuals and families with genetic risks. Genetic counselors aim to explain the implications of genetic testing, discuss risks and options, and offer emotional and psychological support to help individuals make informed decisions regarding their genetic health. Choice A is incorrect because genetic counseling is not focused on treatment but rather on providing information and support. Choice B is incorrect as genetic counselors do not primarily diagnose genetic diseases in newborns but rather provide guidance and support based on existing diagnoses. Choice D is not the purpose of genetic counseling; genetic counselors do not collect DNA samples for research purposes but instead focus on assisting individuals and families in understanding and managing their genetic risks.

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