Nursing Elites

1. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

2. What accurately describes the Linnaean system of classification?

• A. It focuses on evolutionary relationships between organisms.
• B. It uses dichotomous keys for identification.
• C. It groups organisms based on shared functions.
• D. It emphasizes a hierarchical ranking system.

Correct answer: D

Rationale: The Linnaean system of classification, developed by Carl Linnaeus, is based on a hierarchical ranking system where organisms are grouped into categories based on shared characteristics. This system organizes organisms into a hierarchy of increasingly specific categories, from broad to narrow, such as kingdom, phylum, class, order, family, genus, and species. The emphasis on a hierarchical ranking system allows for systematic organization and classification of a wide variety of organisms based on their similarities and differences, making it easier to study and understand the diversity of life forms. Choice A is incorrect because the Linnaean system is not primarily focused on evolutionary relationships but rather on shared characteristics for classification. Choice B is incorrect because dichotomous keys are tools used for identifying organisms, not the fundamental basis of the Linnaean system. Choice C is incorrect as the Linnaean system categorizes organisms based on shared characteristics, not shared functions.

3. What is the principle behind the phenomenon of refraction, where waves bend when entering a new medium?

• A. Change in wavelength
• B. Change in frequency
• C. Change in wave speed
• D. None of the above

Correct answer: C

Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums. Therefore, the correct answer is the change in wave speed (Choice C). Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed. Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.

4. Which structure in the respiratory system is responsible for voice production?

• A. Pharynx
• B. Larynx
• C. Trachea
• D. Bronchi

Correct answer: B

Rationale: The correct answer is the larynx. The larynx, commonly referred to as the voice box, is responsible for voice production in the respiratory system. It contains vocal cords that vibrate to produce sound. The pharynx is a passage for food and air, the trachea is a tubular structure that carries air to and from the lungs, and the bronchi are the main airway passages in the lungs. Therefore, choices A, C, and D are incorrect as they do not play a direct role in voice production.

5. Which of the following is a special property of water?

• A. Water does not easily flow through phospholipid bilayers.
• B. A water molecule's oxygen atom does not allow fish to breathe.
• C. Water is highly cohesive, which explains its high melting point.
• D. Water cannot self-hydrolyze and decompose into hydrogen and oxygen.

Correct answer: C

Rationale: Water is highly cohesive, meaning it is attracted to itself due to its hydrogen bonding properties. This cohesion is the reason why water has a high melting point compared to other liquids of similar molecular weight. It is crucial for the existence of life on Earth as it allows water to remain a liquid within a wide range of temperatures, providing a stable environment for biological processes to occur. Choices A, B, and D are incorrect. Water's cohesive property does not directly relate to its ability to flow through phospholipid bilayers, assist fish in breathing, or self-hydrolyze into hydrogen and oxygen.

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