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. When light enters the fiber at a certain angle, it reflects off the boundary between the core and cladding, ensuring that the light remains trapped within the core and travels along the fiber without significant loss of signal. This total internal reflection allows for efficient transmission of light signals over long distances in optical communication systems.

2. Which hormone, produced by the thyroid gland, plays a crucial role in regulating the body's metabolism, growth, and development?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: c

Rationale: The correct answer is C: Thyroxine. Thyroxine, also known as T4, is a hormone produced by the thyroid gland that plays a crucial role in regulating the body's metabolism, growth, and development. It controls how the body uses energy, affects heart rate, and influences other vital functions. Calcitonin (A) is involved in calcium regulation, not metabolism. Parathyroid hormone (PTH) (B) is produced by the parathyroid glands and regulates calcium and phosphorus levels in the body. Insulin (D) is a hormone produced by the pancreas that regulates blood sugar levels, not metabolism or growth.

3. What can be inferred about the data collected by smart cities?

• A. It is easily accessible and transparent to the public.
• B. It is solely used for optimizing infrastructure and services.
• C. It may raise privacy concerns for individual citizens.
• D. It is always accurate and free from technical errors.

Correct answer: C

Rationale: The passage specifically mentions concerns about data privacy, implying potential issues for individuals.

4. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

• A. Glucose
• B. Sodium and potassium ions
• C. Neurotransmitters
• D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

5. The primary function of the strong nuclear force is:

• A. Binding electrons in atomic orbitals
• B. Binding protons and neutrons within the nucleus
• C. Mediating the attractive force between opposite charges
• D. Mediating the repulsive force between like charges

Correct answer: B

Rationale: The strong nuclear force is responsible for binding protons and neutrons within the nucleus. This force is crucial for overcoming the electrostatic repulsion between positively charged protons in the nucleus, holding the nucleus together. Option A is incorrect as it refers to the role of the electromagnetic force in binding electrons in atomic orbitals. Option C describes the electromagnetic force that mediates the attraction between opposite charges, while option D refers to the electromagnetic force mediating the repulsion between like charges. Understanding the primary function of the strong nuclear force helps explain the stability and structure of atomic nuclei.

6. The muscular diaphragm plays a vital role in respiration. When it contracts, it:

• A. Increases lung volume for inhalation
• B. Decreases lung volume for exhalation
• C. Filters dust and particles from inhaled air
• D. Produces mucus to lubricate the airways

Correct answer: A

Rationale: The diaphragm is a crucial muscle involved in respiration. When the diaphragm contracts, it flattens and moves downwards, increasing the volume in the thoracic cavity. This expansion creates a negative pressure in the lungs, causing air to rush in during inhalation. Therefore, option A, 'Increases lung volume for inhalation,' is the correct answer. The diaphragm's contraction facilitates the breathing process by creating space for the lungs to expand and take in air, making it essential for proper respiration.

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