Nursing Elites

1. In which units is the speed of light in a vacuum measured?

• A. Meters per second
• B. Hertz
• C. Candela
• D. Newton

Correct answer: A

Rationale: The speed of light in a vacuum is commonly measured in units of meters per second. This is because the speed of light is approximately 299,792,458 meters per second in a vacuum, as defined by the International System of Units (SI). The speed of light is a measure of distance covered by light in a given time, hence it is expressed in meters per second. Choices B, C, and D are incorrect. Hertz is a unit of frequency, Candela is a unit of luminous intensity, and Newton is a unit of force. None of these units are relevant for measuring the speed of light, making 'Meters per second' the correct unit of measurement for the speed of light.

2. Which cells myelinate neurons in the CNS?

• A. Schwann cells
• B. Astrocytes
• C. Microglia
• D. Oligodendrocytes

Correct answer: D

Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.

3. Which mineral is essential for muscle function and nerve transmission?

• A. Calcium
• B. Iron
• C. Sodium
• D. Potassium

Correct answer: D

Rationale: Potassium is the correct answer as it is essential for muscle function and nerve transmission. Potassium plays a crucial role in regulating muscle contractions, including the heart's beating, and is vital for transmitting electrical signals within the nervous system. Calcium (Choice A) is important for muscle contraction but is not the primary mineral for nerve transmission. Iron (Choice B) is important for oxygen transport in the blood. Sodium (Choice C) is important for fluid balance but is not primarily responsible for muscle function and nerve transmission.

4. What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?

• A. Entropy
• B. Enthalpy
• C. Gibbs free energy
• D. Heat of reaction

Correct answer: D

Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.

5. Cartilage, a type of connective tissue, provides flexible support in various structures. Which of these structures does NOT contain cartilage?

• A. Ears
• B. Joints
• C. Muscles
• D. Nose

Correct answer: C

Rationale: Cartilage is a type of connective tissue that provides flexible support in various structures. Ears, joints, and the nose all contain cartilage. Muscles, however, are made up of muscle tissue, not cartilage. Therefore, muscles do not contain cartilage. Choice A, ears, choice B, joints, and choice D, nose, are incorrect as they all contain cartilage. Choice C, muscles, is the correct answer as muscles are not composed of cartilage.

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