Nursing Elites

1. What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Interference

Correct answer: a

Rationale: Refraction happens when a wave changes its speed and direction due to encountering a change in medium.

2. The body's first line of defense against pathogens includes:

• A. Phagocytes
• B. Antibodies
• C. Memory B cells
• D. T lymphocytes

Correct answer: A

Rationale: Rationale: Phagocytes are a type of white blood cell that plays a crucial role in the body's innate immune response, which is the first line of defense against pathogens. Phagocytes engulf and digest foreign particles, such as bacteria and viruses, helping to prevent infection and disease. Antibodies (option B) are produced by B cells and are part of the adaptive immune response, not the first line of defense. Memory B cells (option C) are also part of the adaptive immune response and are involved in mounting a faster and stronger response upon re-exposure to a pathogen. T lymphocytes (option D) are another type of white blood cell involved in the adaptive immune response, specifically in cell-mediated immunity.

3. The tiny air sacs in the lungs where gas exchange takes place are called:

• A. Bronchi
• B. Trachea
• C. Alveoli
• D. Pleura

Correct answer: A

Rationale: The correct answer is C: 'Alveoli.' Alveoli are the tiny air sacs in the lungs where gas exchange takes place. Oxygen from the air is diffused into the blood, and carbon dioxide from the blood is diffused into the air in the alveoli. Bronchi (option A) are the large air passages that lead from the trachea into the lungs. Trachea (option B) is the windpipe that connects the larynx to the bronchi. Pleura (option D) is a thin membrane that surrounds the lungs and lines the chest cavity. Understanding these structures is essential for comprehending respiratory function and gas exchange in the human body.

4. 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 the alveolar cells in the lungs that reduces surface tension within the alveoli. This helps to prevent the alveoli from collapsing, making it easier for the lungs to expand and contract during breathing. This action increases lung compliance, which is the ease with which the lungs can be inflated. Trapping dust particles (A) is the role of mucus and cilia in the respiratory system. Surfactant does not produce mucus (C) but rather acts to reduce surface tension. Generating oxygen (D) is the function of the respiratory system as a whole through the process of respiration, and surfactant does not play a direct role in this process.

5. The WBC (white blood cell) type responsible for the initial attack on pathogens is:

• A. Red blood cells
• B. Platelets
• C. Phagocytes
• D. Lymphocytes

Correct answer: C

Rationale: The correct answer is C: Phagocytes. Phagocytes are a type of white blood cell that plays a crucial role in the immune response by engulfing and destroying pathogens. They are the first line of defense against invading microorganisms, initiating the initial attack on pathogens. Red blood cells (option A) are responsible for carrying oxygen, not for immune responses. Platelets (option B) are involved in blood clotting. Lymphocytes (option D) are another type of white blood cell but are mainly responsible for specific immune responses rather than the initial attack on pathogens.

6. Newton's rings are a visual demonstration of:

• A. Diffraction
• B. Doppler effect
• C. Polarization
• D. Thin-film interference

Correct answer: D

Rationale: Newton's rings are a series of concentric colored rings observed when light is reflected between a spherical surface and a flat surface. This phenomenon is a result of thin-film interference, which occurs due to the varying thickness of the air gap between the surfaces. The interference of light waves results in constructive and destructive interference, leading to the formation of the rings. Diffraction, the bending of light around obstacles, is not the cause of Newton's rings. The Doppler effect involves the change in frequency of waves due to motion and is not relevant in this context. Polarization refers to the orientation of electromagnetic waves, which is not the primary factor in the formation of Newton's rings. Therefore, the correct answer is D: Thin-film interference.

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