Nursing Elites

1. 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.

2. What is the role of surfactant in the respiratory system?

• A. To trap dust particles
• B. To increase lung compliance
• C. To produce mucus
• D. To generate oxygen during respiration

Correct answer: B

Rationale: The correct answer is B: To increase lung compliance. Surfactant is a substance produced by type II alveolar cells in the lungs that reduces surface tension in the alveoli. This reduction in surface tension helps to increase lung compliance, making it easier for the lungs to expand and contract during breathing. Improved lung compliance is essential for efficient gas exchange in the respiratory system, facilitating oxygen uptake and carbon dioxide removal. Choices A, C, and D are incorrect because surfactant does not trap dust particles, produce mucus, or generate oxygen during respiration. Instead, its primary function lies in reducing surface tension to prevent alveolar collapse and improve lung compliance for optimal gas exchange.

3. What is correct about the hormones that stimulate male and female organs to produce male and female sex hormones?

• A. Female organs are stimulated by female hormones and male organs by male hormones.
• B. The same hormones that produce male or female sex characteristics stimulate the organs.
• C. The same hormones stimulate both male and female organs to produce sex hormones.
• D. The hypothalamus stimulates the pituitary gland's secretion of male and female hormones.

Correct answer: C

Rationale: The correct answer is C. The same hormones stimulate both male and female organs to produce sex hormones. Hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced by the pituitary gland and act on the ovaries in females and the testes in males to stimulate the production of sex hormones (estrogen and progesterone in females, testosterone in males). Therefore, the same hormones stimulate both male and female organs to produce sex hormones. Choices A, B, and D are incorrect because they do not accurately describe the relationship between hormones and the stimulation of male and female organs to produce sex hormones.

4. In nuclear physics, the term 'barn' is a unit commonly used to quantify:

• A. Energy
• B. Radioactivity
• C. Nuclear cross-section
• D. Half-life

Correct answer: C

Rationale: In nuclear physics, the term 'barn' is a unit used to quantify nuclear cross-section. Nuclear cross-section is a measure of the probability of a nuclear reaction occurring when an atomic nucleus interacts with a particle or another nucleus. The barn is a unit of area equal to 10^-28 square meters; it is commonly used to describe the cross-sectional area of atomic nuclei for nuclear reactions. Choice A, 'Energy,' is incorrect because a barn is not a unit for measuring energy; it is a unit of area. Choice B, 'Radioactivity,' is incorrect as radioactivity is typically measured in units like becquerels. Choice D, 'Half-life,' is also incorrect as half-life is a measure of the time it takes for half of a substance to decay, not related to the concept of a barn as a unit of nuclear cross-section.

5. Which gland, often referred to as the 'master gland' of the endocrine system and located at the base of the brain, secretes various hormones that control other glands?

• A. Thyroid gland
• B. Pituitary gland
• C. Adrenal gland
• D. Pancreas

Correct answer: B

Rationale: The pituitary gland is correctly known as the 'master gland' of the endocrine system. It is situated at the base of the brain and plays a crucial role in secreting a variety of hormones that regulate the functions of other endocrine glands in the body. These hormones control growth, metabolism, reproduction, and various other essential bodily functions. The other choices, thyroid gland, adrenal gland, and pancreas, are incorrect as they do not serve as the 'master gland' of the endocrine system nor are located at the base of the brain like the pituitary gland.

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