Nursing Elites

1. Reactions requiring light energy to proceed are classified as:

• A. Combustion reactions
• B. Endothermic reactions
• C. Photochemical reactions
• D. Double displacement reactions

Correct answer: C

Rationale: The correct answer is C: "Photochemical reactions." Photochemical reactions are a type of chemical reaction that requires light energy to proceed. During a photochemical reaction, light energy is absorbed by a substance, leading to changes in its chemical structure or properties. This process is different from combustion reactions (A), which involve the rapid combination of a fuel with oxygen to release heat and light energy. Endothermic reactions (B) absorb heat energy, not light energy, to proceed. Double displacement reactions (D) involve the exchange of ions between reactants, but do not specifically require light energy to occur. Therefore, the most appropriate classification for reactions requiring light energy is photochemical reactions.

2. 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.

3. Vaccines work by stimulating the immune system to develop memory without causing full-blown illness. What type of molecule in a vaccine typically triggers the immune response?

• A. Toxins produced by the pathogen
• B. Live, attenuated (weakened) forms of the pathogen
• C. Inactivated (dead) forms of the pathogen
• D. Antigens (specific molecules) from the pathogen

Correct answer: D

Rationale: The correct answer is D: Antigens (specific molecules) from the pathogen. Vaccines contain antigens, which are specific molecules from the pathogen that trigger the immune response without causing the full-blown illness. By presenting these antigens to the immune system, vaccines stimulate the production of memory cells that can recognize and combat the pathogen in the future. Options A, B, and C are incorrect because vaccines typically do not contain toxins, live attenuated forms, or inactivated forms of the pathogen. Instead, they contain specific antigens to induce an immune response without causing the actual disease.

4. Which skin condition is characterized by patches of inflamed, reddened skin and is often triggered by allergens or stress?

• A. Eczema
• B. Psoriasis
• C. Acne
• D. Vitiligo

Correct answer: A

Rationale: The correct answer is A: Eczema. Eczema is a skin condition characterized by patches of inflamed, reddened skin that can be triggered by allergens or stress. It is a chronic condition that can cause itching and discomfort. Psoriasis (option B) is a different skin condition characterized by red, scaly patches on the skin. Acne (option C) is a common skin condition characterized by pimples and clogged pores. Vitiligo (option D) is a condition where the skin loses its pigment, resulting in white patches. Therefore, eczema best fits the description provided in the question.

5. In nuclear transmutation, a target nucleus is bombarded with a particle to create:

• A. A heavier isotope of the same element
• B. A lighter isotope of the same element
• C. An entirely new element
• D. A chain reaction of nuclear fission

Correct answer: C

Rationale: In nuclear transmutation, a target nucleus is bombarded with a particle to create an entirely new element. During this process, the target nucleus absorbs the incoming particle, resulting in changes to its atomic number and sometimes its mass number. These changes can lead to the creation of a different element altogether. This is a fundamental concept in nuclear chemistry and is used in various applications, including the creation of new isotopes for research or medical purposes. Options A and B are incorrect because transmutation involves creating a different element, not just a heavier or lighter isotope of the same element. Option D, a chain reaction of nuclear fission, is also incorrect as it refers to a different process where a nucleus splits into smaller fragments, releasing energy and more neutrons to sustain the chain reaction.

6. What happens to the density of a substance if its mass increases while its volume remains constant?

• A. Density increases
• B. Density decreases
• C. Density remains constant
• D. Density becomes zero

Correct answer: a

Rationale: Density is the ratio of mass to volume. If the mass increases while the volume remains constant, the density will increase as there is more mass in the same volume.

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